diff --git a/qa/health-server-pagination.test.cjs b/qa/health-server-pagination.test.cjs
index ca64951..b18b876 100644
--- a/qa/health-server-pagination.test.cjs
+++ b/qa/health-server-pagination.test.cjs
@@ -5,13 +5,13 @@ const fs=require('node:fs');
 const HealthViews=require('../src/mi_fitness_mcp/web_assets/static/js/health-views.js');
 function summary(kind='stress',number=1,total=21){return {status:'ok',kind,range:{start:'2026-10-15',end:'2026-10-17'},statistics:{count:total,primary_mean:33,primary_min:10,primary_max:60},coverage:1,stride:1,points:[{date:'2026-10-16',values:[33],missing:false}],page:{number,size:10,total,rows:[{timestamp:'2026-10-16T00:00:00Z',stress_score:number}]}};}
 function fixture(){
- const nodes=new Map(),links=[],requests=[],calendars=[];
+ const nodes=new Map(),links=[],forms=[],elements=[],requests=[],calendars=[];
  const get=id=>{if(!nodes.has(id))nodes.set(id,{value:({startDate:'2026-10-15',endDate:'2026-10-17',napsSelect:'true'})[id]||'',textContent:'',innerHTML:'',checked:false,setAttribute(){},classList:{toggle(){},add(){},remove(){}},querySelector(){return get(id+'-table');}});return nodes.get(id);};
- const context=vm.createContext({HealthViews,AbortController,console,performance,URL,document:{getElementById:get,querySelectorAll(){return [];},addEventListener(){},createElement(){const a={click(){links.push(this.href);},remove(){}};return a;},body:{appendChild(){}}},localStorage:{getItem(){return '';},setItem(){}},setTimeout(){},setInterval(){},clearTimeout(){},clearInterval(){},fetch:url=>new Promise(resolve=>{if(url.startsWith('/api/calendar'))calendars.push({url,resolve});else requests.push({url,resolve});})});
+ const context=vm.createContext({HealthViews,AbortController,console,performance,URL,document:{getElementById:get,querySelectorAll(){return [];},addEventListener(){},createElement(tag){const element={tag,children:[],appendChild(child){this.children.push(child);},click(){links.push(this.href);},submit(){forms.push({method:this.method,action:this.action,fields:this.children.map(child=>({name:child.name,value:child.value,type:child.type}))});},remove(){this.removed=true;}};elements.push(element);return element;},body:{appendChild(){}}},localStorage:{getItem(){return '';},setItem(){}},setTimeout(){},setInterval(){},clearTimeout(){},clearInterval(){},fetch:url=>new Promise(resolve=>{if(url.startsWith('/api/calendar'))calendars.push({url,resolve});else requests.push({url,resolve});})});
  for(const name of ['health-ui','app'])vm.runInContext(fs.readFileSync(`src/mi_fitness_mcp/web_assets/static/js/${name}.js`,'utf8'),context);
  vm.runInContext('showToast=()=>{};state.activeTab="stress";',context);
  const reply=(i,p)=>requests[i].resolve({status:200,ok:true,text:async()=>JSON.stringify(p)});
- return {context,get,links,requests,calendars,reply,run:code=>vm.runInContext(code,context)};
+ return {context,get,links,forms,elements,requests,calendars,reply,run:code=>vm.runInContext(code,context)};
 }
 test('test_pagination_fetches_only_page_and_preserves_chart',async()=>{
  const f=fixture(),initial=f.run('loadHealthView("stress")');assert.match(f.requests[0].url,/^\/proxy\/api\/views\/stress\?/);f.reply(0,summary());await initial;
@@ -77,3 +77,14 @@ test('out-of-order overview loads preserve new range values and inspector',async
  f.reply(1,{status:'ok',data:{steps:42}});await current;const inspector=f.get('inspectorBody').innerHTML;
  f.reply(0,{status:'ok',data:{steps:999}});await old;assert.equal(f.get('statSteps').textContent,'42');assert.equal(f.get('inspectorBody').innerHTML,inspector);assert.match(f.get('overviewRange').textContent,/2026-10-16 至 2026-10-17/);
 });
+
+for(const source of ['input','state'])test(`native export submits the selected ${source} key only in a temporary POST form`,async()=>{
+ const f=fixture();
+ f.get('apiKeyInput').value='  synthetic-input-key  ';
+ if(source==='state')f.run('state.apiKey="synthetic-state-key"');
+ const selected=source==='state'?'synthetic-state-key':'synthetic-input-key';
+ const initial=f.run('loadHealthView("stress")');f.reply(0,summary());await initial;
+ f.run('exportHealthRecords("stress")');assert.equal(f.forms.length,1);assert.equal(f.links.length,0);assert.equal(f.requests.length,1);
+ const form=f.forms[0];assert.equal(form.method,'POST');assert.match(form.action,/^\/proxy\/api\/views\/stress\/export\?/);assert.doesNotMatch(form.action,/synthetic|api_key|page=/);assert.deepEqual(form.fields,[{name:'api_key',value:selected,type:'hidden'}]);
+ const node=f.elements.find(element=>element.tag==='form');assert.equal(node.removed,true);assert.equal(node.children[0].value,'');assert.equal(node.autocomplete,'off');
+});
diff --git a/src/mi_fitness_mcp/web.py b/src/mi_fitness_mcp/web.py
index c68051f..d946e62 100644
--- a/src/mi_fitness_mcp/web.py
+++ b/src/mi_fitness_mcp/web.py
@@ -155,6 +155,8 @@ def create_app(
         # Attach API Key (Server env priority, otherwise pass through client key)
         server_api_key = app.config["API_KEY"]
         if server_api_key:
+            forward_headers = {key: value for key, value in forward_headers.items()
+                               if key.lower() != "x-api-key"}
             forward_headers["X-API-Key"] = server_api_key
 
         # Attach Admin Key if configured
@@ -166,12 +168,22 @@ def create_app(
                 forward_headers = {key: value for key, value in forward_headers.items()
                                    if key.lower() != "x-api-key"}
 
-        body = request.get_data() if request.method in ("POST", "PUT", "PATCH", "DELETE") else None
+        parts = clean_subpath.split("/")
+        is_export = (request.method in {"GET", "POST"} and len(parts) == 4
+            and parts[:2] == ["api", "views"] and parts[3] == "export"
+            and parts[2] in {"activity", "heartrate", "sleep", "workouts", "body", "spo2", "stress", "abnormal"})
+        body = request.get_data() if not is_export and request.method in ("POST", "PUT", "PATCH", "DELETE") else None
 
         started = time.perf_counter()
         try:
-            parts = clean_subpath.split("/")
-            if request.method == "GET" and len(parts) == 4 and parts[:2] == ["api", "views"] and parts[3] == "export":
+            if is_export:
+                # 仅导出接受原生下载表单；上游仍为无请求体的只读 GET。
+                export_key = server_api_key or (request.form.get("api_key") if request.method == "POST" else None)
+                if export_key:
+                    forward_headers = {key: value for key, value in forward_headers.items() if key.lower() != "x-api-key"}
+                    forward_headers["X-API-Key"] = export_key
+                if request.method == "POST":
+                    forward_headers = {key: value for key, value in forward_headers.items() if key.lower() != "content-type"}
                 upstream_request = http_client.build_request("GET", target_url, headers=forward_headers)
                 upstream_resp = http_client.send(upstream_request, stream=True)
                 elapsed_ms = round((time.perf_counter() - started) * 1000, 2)
diff --git a/src/mi_fitness_mcp/web_assets/static/js/health-ui.js b/src/mi_fitness_mcp/web_assets/static/js/health-ui.js
index ef3c893..a87ff0c 100644
--- a/src/mi_fitness_mcp/web_assets/static/js/health-ui.js
+++ b/src/mi_fitness_mcp/web_assets/static/js/health-ui.js
@@ -109,8 +109,18 @@ async function healthPage(kind,page){
 }
 function exportHealthRecords(kind){
   const saved=state.healthViews[kind];if(!saved||!saved.isCurrent())return;
+  const path='/proxy'+healthPath(kind,'/export'),key=getHeaders()['X-API-Key'];
+  if(key){
+    // 原生附件下载通过短暂表单传查询身份，Key 不进入 URL 或长期 DOM。
+    const form=document.createElement('form'),input=document.createElement('input');
+    form.method='POST';form.action=path;form.hidden=true;form.autocomplete='off';
+    input.type='hidden';input.name='api_key';input.value=key;
+    form.appendChild(input);document.body.appendChild(form);
+    try{form.submit();}finally{input.value='';form.remove();}
+    return;
+  }
   const link=document.createElement('a');
-  link.href='/proxy'+healthPath(kind,'/export');link.download='';
+  link.href=path;link.download='';
   document.body.appendChild(link);link.click();link.remove();
 }
 function initHealthViews(){
diff --git a/tests/test_web_streaming.py b/tests/test_web_streaming.py
index 3c3b493..765728c 100644
--- a/tests/test_web_streaming.py
+++ b/tests/test_web_streaming.py
@@ -29,13 +29,14 @@ def make_client(monkeypatch):
     return app.test_client()
 
 
+@pytest.mark.parametrize("method", ["GET", "POST"])
 @respx.mock
-def test_stream_disconnect_closes_cursor_and_proxy_response(monkeypatch):
+def test_stream_disconnect_closes_cursor_and_proxy_response(monkeypatch, method):
     stream = TrackedStream()
     route = respx.get("http://synthetic-backend/api/views/stress/export").mock(return_value=httpx.Response(200,
         stream=stream, headers={"Content-Type": "text/csv; charset=utf-8", "Content-Disposition": 'attachment; filename="synthetic.csv"', "X-API-Key": "must-not-leak", "X-Admin-Key": "must-not-leak", "Authorization": "must-not-leak", "Set-Cookie": "must-not-leak"}))
     client = make_client(monkeypatch)
-    response = client.get("/proxy/api/views/stress/export", auth=("admin", "synthetic-web-password"), buffered=False)
+    response = client.open("/proxy/api/views/stress/export", method=method, data={"api_key": "synthetic-browser-key"} if method == "POST" else None, auth=("admin", "synthetic-web-password"), buffered=False)
     assert response.status_code == 200
     assert response.is_streamed
     assert 0 < stream.consumed < 30
@@ -48,13 +49,14 @@ def test_stream_disconnect_closes_cursor_and_proxy_response(monkeypatch):
     assert stream.consumed < 30
 
 
+@pytest.mark.parametrize("method", ["GET", "POST"])
 @respx.mock
-def test_stream_normal_completion_and_error_release_upstream(monkeypatch):
+def test_stream_normal_completion_and_error_release_upstream(monkeypatch, method):
     client = make_client(monkeypatch)
     for fail in [False, True]:
         stream = TrackedStream(fail)
         respx.get("http://synthetic-backend/api/views/body/export").mock(return_value=httpx.Response(200, stream=stream, headers={"Content-Type": "text/csv"}))
-        response = client.get("/proxy/api/views/body/export", auth=("admin", "synthetic-web-password"), buffered=False)
+        response = client.open("/proxy/api/views/body/export", method=method, data={"api_key": "synthetic-browser-key"} if method == "POST" else None, auth=("admin", "synthetic-web-password"), buffered=False)
         if fail:
             with pytest.raises(httpx.ReadError):
                 list(response.response)
@@ -78,3 +80,78 @@ def test_export_connection_failure_uses_existing_error_shape(monkeypatch):
     assert response.status_code == 502
     assert response.json["error"] == "Flask 代理无法访问后端"
     assert "X-Upstream-Time-Ms" in response.headers
+
+
+@respx.mock
+def test_form_export_uses_the_same_selected_user_as_summary_without_key_in_url(monkeypatch):
+    monkeypatch.setenv("MI_FITNESS_WEB_PASSWORD", "synthetic-web-password")
+    monkeypatch.delenv("MI_FITNESS_API_KEY", raising=False)
+    monkeypatch.delenv("MI_FITNESS_ADMIN_KEY", raising=False)
+    client = create_app(backend_url="http://synthetic-backend").test_client()
+    selected_key = "synthetic-selected-key"
+    seen = []
+
+    def user_response(request):
+        selected = request.headers.get("X-API-Key") == selected_key
+        seen.append(request)
+        if not selected:
+            return httpx.Response(401, json={"status": "error"})
+        if request.url.path.endswith("/export"):
+            return httpx.Response(200, content=b"synthetic-selected-user,csv", headers={"Content-Type": "text/csv", "Content-Disposition": 'attachment; filename="synthetic.csv"'})
+        return httpx.Response(200, json={"status": "ok", "synthetic_user": "synthetic-selected-user"})
+
+    respx.get("http://synthetic-backend/api/views/stress").mock(side_effect=user_response)
+    respx.get("http://synthetic-backend/api/views/stress/export").mock(side_effect=user_response)
+    auth = ("admin", "synthetic-web-password")
+    query = "?start_date=2026-10-01&end_date=2026-10-17&pressure_level=mild&limit=11"
+    summary = client.get("/proxy/api/views/stress" + query, auth=auth, headers={"X-API-Key": selected_key})
+    export = client.post("/proxy/api/views/stress/export" + query, data={"api_key": selected_key, "unexpected": "must-not-forward"}, auth=auth)
+    assert summary.status_code == export.status_code == 200
+    assert summary.json["synthetic_user"].encode() in export.data
+    assert len(seen) == 2
+    assert all(request.headers["X-API-Key"] == selected_key for request in seen)
+    assert seen[1].method == "GET"
+    assert seen[1].content == b""
+    assert selected_key not in str(seen[1].url)
+    assert "unexpected" not in str(seen[1].url)
+    assert seen[1].url.query == seen[0].url.query
+    assert "application/x-www-form-urlencoded" not in seen[1].headers.get("Content-Type", "")
+    export.close()
+
+
+@respx.mock
+def test_server_key_wins_over_form_and_browser_header(monkeypatch):
+    client = make_client(monkeypatch)
+    summary_route = respx.get("http://synthetic-backend/api/views/activity").mock(return_value=httpx.Response(200, json={"status": "ok"}))
+    summary = client.get("/proxy/api/views/activity", headers={"X-API-Key": "synthetic-header-key"}, auth=("admin", "synthetic-web-password"))
+    assert summary.status_code == 200
+    assert summary_route.calls[0].request.headers.get_list("X-API-Key") == ["synthetic-api-key"]
+    route = respx.get("http://synthetic-backend/api/views/activity/export").mock(return_value=httpx.Response(200, content=b"synthetic", headers={"Content-Type": "text/csv"}))
+    response = client.post("/proxy/api/views/activity/export", data={"api_key": "synthetic-form-key"}, headers={"X-API-Key": "synthetic-header-key"}, auth=("admin", "synthetic-web-password"))
+    assert response.status_code == 200
+    assert route.calls[0].request.headers.get_list("X-API-Key") == ["synthetic-api-key"]
+    assert route.calls[0].request.content == b""
+    response.close()
+
+
+@respx.mock
+def test_only_whitelisted_exports_translate_post_and_form_key(monkeypatch):
+    client = make_client(monkeypatch)
+    for path in ["api/views/not-a-kind/export", "api/views/stress/records", "api/sync"]:
+        route = respx.post("http://synthetic-backend/" + path).mock(return_value=httpx.Response(200, json={"status": "ok"}))
+        response = client.post("/proxy/" + path, data={"api_key": "synthetic-form-key"}, auth=("admin", "synthetic-web-password"))
+        assert response.status_code == 200
+        request = route.calls[0].request
+        assert request.method == "POST"
+        assert request.content == b"api_key=synthetic-form-key"
+        assert request.headers["X-API-Key"] == "synthetic-api-key"
+
+
+@respx.mock
+def test_form_export_retains_basic_host_and_origin_checks(monkeypatch):
+    client = make_client(monkeypatch)
+    path = "/proxy/api/views/stress/export"
+    assert client.post(path, data={"api_key": "synthetic"}).status_code == 401
+    auth = ("admin", "synthetic-web-password")
+    assert client.post(path, data={"api_key": "synthetic"}, auth=auth, headers={"Origin": "https://untrusted.example"}).status_code == 403
+    assert client.post(path, data={"api_key": "synthetic"}, auth=auth, headers={"Host": "untrusted.example"}).status_code == 403