diff --git a/app/canvas/[id]/CanvasEditorLegacyPageClient.tsx b/app/canvas/[id]/CanvasEditorLegacyPageClient.tsx
index c464da785..d83c30f8c 100644
--- a/app/canvas/[id]/CanvasEditorLegacyPageClient.tsx
+++ b/app/canvas/[id]/CanvasEditorLegacyPageClient.tsx
@@ -5215,8 +5215,13 @@ export default function CanvasEditorLegacyPage({
           return;
         }
 
+        const beforeRead = useCanvasStore.getState();
         const result = await canvasService.getProject(id);
-        if (cancelled || canvasRemoteOperationActive.current || !result.success || !result.data) return;
+        const current = useCanvasStore.getState();
+        if (
+          cancelled || canvasRemoteOperationActive.current || !result.success || !result.data ||
+          current.projectId !== id || current.nodes !== beforeRead.nodes || current.edges !== beforeRead.edges
+        ) return;
         useCanvasStore.getState().markAgentOperationRefresh();
         hydrateCanvasProject(result.data);
         lastLocalCanvasMutationAtRef.current = Date.now();
diff --git a/app/canvas/[id]/style-pro/page.tsx b/app/canvas/[id]/style-pro/page.tsx
index 0ba03f4aa..2e91c6521 100644
--- a/app/canvas/[id]/style-pro/page.tsx
+++ b/app/canvas/[id]/style-pro/page.tsx
@@ -48,8 +48,13 @@ export default function CanvasStyleProPage() {
       const canvasData = result.data.canvasData;
       const latestState = useCanvasStore.getState();
       setProject(result.data.id, result.data.title);
-      if (latestState.nodes.length === 0 && latestState.edges.length === 0) {
+      if (
+        latestState.projectId !== id ||
+        (latestState.nodes.length === 0 && latestState.edges.length === 0)
+      ) {
         loadCanvas(canvasData);
+        const revision = String(result.data.updatedAt || "");
+        useCanvasStore.getState().setCanvasRevision(revision, revision);
         return;
       }
 
diff --git a/services/canvas/index.ts b/services/canvas/index.ts
index 597f7c623..8fd455d9d 100644
--- a/services/canvas/index.ts
+++ b/services/canvas/index.ts
@@ -95,18 +95,19 @@ function normalizeRevisionText(value: unknown) {
   return String(value || "").trim();
 }
 
-function syncCanvasStoreRevisionFromUpdatedAt(updatedAt: unknown): void {
+function syncCanvasStoreRevisionFromUpdatedAt(projectId: string, updatedAt: unknown): void {
   if (typeof window === "undefined") return;
   const revision = normalizeRevisionText(updatedAt);
   if (!revision) return;
-  useCanvasStore.getState().setCanvasRevision(revision, revision);
+  const current = useCanvasStore.getState();
+  if (current.projectId === projectId) current.setCanvasRevision(revision, revision);
 }
 
 function syncCanvasStoreRevisionFromProject(
-  project?: { canvasData?: CanvasState | null; updatedAt?: Date | string } | null
+  project?: { id: string; canvasData?: CanvasState | null; updatedAt?: Date | string } | null
 ): void {
   if (!project?.canvasData) return;
-  syncCanvasStoreRevisionFromUpdatedAt(project.updatedAt);
+  syncCanvasStoreRevisionFromUpdatedAt(project.id, project.updatedAt);
 }
 
 export interface NormalizedCropRect {
@@ -203,9 +204,6 @@ export const canvasService = {
     try {
       const response = await fetch(`/api/canvas/${id}`);
       const data = await response.json();
-      if (data?.success) {
-        syncCanvasStoreRevisionFromProject(data.data);
-      }
       return data;
     } catch (error) {
       return { success: false, error: '获取画布失败' };
@@ -335,7 +333,7 @@ export const canvasService = {
         };
       }
       if (data?.success) {
-        syncCanvasStoreRevisionFromUpdatedAt(data?.data?.updatedAt);
+        syncCanvasStoreRevisionFromUpdatedAt(id, data?.data?.updatedAt);
       }
       return data as ApiResponse;
     } catch (error) {
diff --git a/tests/routes/canvas-chat-helpers.test.ts b/tests/routes/canvas-chat-helpers.test.ts
index b874a2f38..cc1fa25e0 100644
--- a/tests/routes/canvas-chat-helpers.test.ts
+++ b/tests/routes/canvas-chat-helpers.test.ts
@@ -808,6 +808,7 @@ test.describe("canvas chat pure helpers", () => {
   });
 
   test("canvas service save uses store revision fallback when options are omitted", async () => {
+    useCanvasStore.getState().setProject("11111111-1111-4111-8111-111111111111");
     const canvasData = {
       nodes: [],
       edges: [],
@@ -885,7 +886,7 @@ test.describe("canvas chat pure helpers", () => {
     });
   });
 
-  test("canvas service keeps store revision aligned after project load and save", async () => {
+  test("canvas revision advances after applying the fetched snapshot and saving the current project", async () => {
     const canvasData = {
       nodes: [],
       edges: [],
@@ -915,6 +916,7 @@ test.describe("canvas chat pure helpers", () => {
       },
     ];
 
+    useCanvasStore.getState().setProject("11111111-1111-4111-8111-111111111111");
     useCanvasStore.getState().setCanvasRevision(null, null);
     Object.defineProperty(globalThis, "window", {
       configurable: true,
@@ -929,7 +931,11 @@ test.describe("canvas chat pure helpers", () => {
       }) as Response) as typeof fetch;
 
     try {
-      await canvasService.getProject("11111111-1111-4111-8111-111111111111");
+      const result = await canvasService.getProject("11111111-1111-4111-8111-111111111111");
+      expect(useCanvasStore.getState().canvasRevision).toBeNull();
+      useCanvasStore.getState().loadCanvas(result.data!.canvasData);
+      const revision = String(result.data!.updatedAt);
+      useCanvasStore.getState().setCanvasRevision(revision, revision);
       expect(useCanvasStore.getState().canvasRevision).toBe(
         "2026-06-22T00:01:00.000Z"
       );
diff --git a/tests/routes/canvas-toolbar-capability.test.ts b/tests/routes/canvas-toolbar-capability.test.ts
index 6622813c3..38d49dbd0 100644
--- a/tests/routes/canvas-toolbar-capability.test.ts
+++ b/tests/routes/canvas-toolbar-capability.test.ts
@@ -136,6 +136,71 @@ test("metadata changes never adopt an unseen remote canvas revision", async () =
   expect(useCanvasStore.getState().canvasRevision).toBe("r1");
 });
 
+test("reading a result without applying it cannot authorize an old snapshot to overwrite the result", async () => {
+  const previousWindow = Object.getOwnPropertyDescriptor(globalThis, "window");
+  Object.defineProperty(globalThis, "window", { configurable: true, value: {} });
+  let remoteNodes = [node("source"), node("result")];
+  globalThis.fetch = (async (_url, options) => {
+    if (options?.method === "PUT") {
+      const body = JSON.parse(String(options.body));
+      if (body.baseCanvasRevision !== "r2") return Response.json({ success: false, error: "画布已更新" }, { status: 409 });
+      remoteNodes = body.canvasData.nodes;
+      return Response.json({ success: true, data: { updatedAt: "r3" } });
+    }
+    return Response.json({ success: true, data: { id: "project-a", updatedAt: "r2", canvasData: { nodes: remoteNodes, edges: [] } } });
+  }) as typeof fetch;
+  try {
+    await canvasService.getProject("project-a");
+    const saved = await canvasService.saveCanvasState("project-a", useCanvasStore.getState().getCanvasState());
+    expect(saved).toMatchObject({ success: false, status: 409 });
+    expect(remoteNodes.map(n => n.id)).toEqual(["source", "result"]);
+    expect(useCanvasStore.getState().canvasRevision).toBe("r1");
+  } finally {
+    if (previousWindow) Object.defineProperty(globalThis, "window", previousWindow);
+    else Reflect.deleteProperty(globalThis, "window");
+  }
+});
+
+test("a delayed read cannot change the revision of a newly selected project", async () => {
+  const previousWindow = Object.getOwnPropertyDescriptor(globalThis, "window");
+  Object.defineProperty(globalThis, "window", { configurable: true, value: {} });
+  let complete!: (response: Response) => void;
+  globalThis.fetch = (() => new Promise<Response>(resolve => { complete = resolve; })) as typeof fetch;
+  try {
+    const pending = canvasService.getProject("project-a");
+    useCanvasStore.getState().setProject("project-b");
+    useCanvasStore.getState().loadCanvas({ nodes: [node("other") as any], edges: [] });
+    useCanvasStore.getState().setCanvasRevision("r9", "r9");
+    complete(Response.json({ success: true, data: { id: "project-a", updatedAt: "r2", canvasData: { nodes: [node("result")], edges: [] } } }));
+    await pending;
+    expect(useCanvasStore.getState().canvasRevision).toBe("r9");
+    expect(useCanvasStore.getState().nodes.map(n => n.id)).toEqual(["other"]);
+  } finally {
+    if (previousWindow) Object.defineProperty(globalThis, "window", previousWindow);
+    else Reflect.deleteProperty(globalThis, "window");
+  }
+});
+
+test("a delayed save cannot change the revision of a newly selected project", async () => {
+  const previousWindow = Object.getOwnPropertyDescriptor(globalThis, "window");
+  Object.defineProperty(globalThis, "window", { configurable: true, value: {} });
+  let complete!: (response: Response) => void;
+  globalThis.fetch = (() => new Promise<Response>(resolve => { complete = resolve; })) as typeof fetch;
+  try {
+    const pending = canvasService.saveCanvasState("project-a", useCanvasStore.getState().getCanvasState());
+    useCanvasStore.getState().setProject("project-b");
+    useCanvasStore.getState().loadCanvas({ nodes: [node("other") as any], edges: [] });
+    useCanvasStore.getState().setCanvasRevision("r9", "r9");
+    complete(Response.json({ success: true, data: { updatedAt: "r2" } }));
+    await pending;
+    expect(useCanvasStore.getState().canvasRevision).toBe("r9");
+    expect(useCanvasStore.getState().nodes.map(n => n.id)).toEqual(["other"]);
+  } finally {
+    if (previousWindow) Object.defineProperty(globalThis, "window", previousWindow);
+    else Reflect.deleteProperty(globalThis, "window");
+  }
+});
+
 test("a result merge conflict retains both the local edit and its original revision", async () => {
   globalThis.fetch = (async (url) => {
     if (String(url).endsWith("/capabilities")) {