diff --git a/apps/web/app/versions/[id]/page.tsx b/apps/web/app/versions/[id]/page.tsx
index bf09f4f..0a26db7 100644
--- a/apps/web/app/versions/[id]/page.tsx
+++ b/apps/web/app/versions/[id]/page.tsx
@@ -393,15 +393,24 @@ export default function VersionDetailPage() {
 
                   // 调研阶段
                   const researchPlans = versionPlans.filter((p) => p.type === 'research');
-                  const researchCal = calcCalendar(researchPlans.map((p) => p.startTime), researchPlans.filter((p) => p.status === 'completed').map((p) => p.endTime));
+                  const researchCal = calcCalendar(
+                    researchPlans.filter((p) => p.actualStartAt).map((p) => p.actualStartAt!),
+                    researchPlans.filter((p) => p.completedAt).map((p) => p.completedAt!),
+                  );
 
                   // 产品方案阶段
                   const productPlans = versionPlans.filter((p) => p.type === 'product');
-                  const productCal = calcCalendar(productPlans.map((p) => p.startTime), productPlans.filter((p) => p.status === 'completed').map((p) => p.endTime));
+                  const productCal = calcCalendar(
+                    productPlans.filter((p) => p.actualStartAt).map((p) => p.actualStartAt!),
+                    productPlans.filter((p) => p.completedAt).map((p) => p.completedAt!),
+                  );
 
                   // UI设计阶段
                   const uiPlans = versionPlans.filter((p) => p.type === 'ui');
-                  const uiCal = calcCalendar(uiPlans.map((p) => p.startTime), uiPlans.filter((p) => p.status === 'completed').map((p) => p.endTime));
+                  const uiCal = calcCalendar(
+                    uiPlans.filter((p) => p.actualStartAt).map((p) => p.actualStartAt!),
+                    uiPlans.filter((p) => p.completedAt).map((p) => p.completedAt!),
+                  );
 
                   // 开发阶段
                   const devCal = calcCalendar(
@@ -434,9 +443,8 @@ export default function VersionDetailPage() {
 
                   // 调研/产品/UI 用 startTime→endTime 计算
                   versionPlans.forEach((p) => {
-                    if (!p.owner || !p.startTime) return;
-                    const end = p.status === 'completed' ? p.endTime : undefined;
-                    const hours = calcActualHoursByDates(p.startTime.slice(0, 10), end?.slice(0, 10));
+                    if (!p.owner || !p.actualStartAt) return;
+                    const hours = calcActualHoursByDates(p.actualStartAt, p.completedAt);
                     addHours(p.owner, p.type === 'research' ? 'research' : p.type === 'product' ? 'product' : 'ui', hours);
                   });
                   versionDevTasks.forEach((t) => {
diff --git a/apps/web/lib/version-plan.ts b/apps/web/lib/version-plan.ts
index d18dea3..b64b809 100644
--- a/apps/web/lib/version-plan.ts
+++ b/apps/web/lib/version-plan.ts
@@ -24,6 +24,7 @@ export interface VersionPlan {
   resultFileData?: string;
   remark?: string;
   overdueReason?: string;
+  actualStartAt?: string;
   createdAt: string;
   completedAt?: string;
   addedBy: string;
diff --git a/apps/web/stores/useVersionPlanStore.ts b/apps/web/stores/useVersionPlanStore.ts
index 2f757c7..891b26a 100644
--- a/apps/web/stores/useVersionPlanStore.ts
+++ b/apps/web/stores/useVersionPlanStore.ts
@@ -43,7 +43,18 @@ export const useVersionPlanStore = create<VersionPlanState>((set, get) => ({
   },
 
   updatePlan: (id, data) => {
-    const plans = get().plans.map((p) => p.id === id ? { ...p, ...data } : p);
+    const now = new Date().toISOString();
+    const plans = get().plans.map((p) => {
+      if (p.id !== id) return p;
+      const patch = { ...data };
+      if (patch.status === 'in_progress' && !p.actualStartAt) {
+        (patch as any).actualStartAt = now;
+      }
+      if (patch.status === 'completed' && !p.completedAt) {
+        (patch as any).completedAt = now;
+      }
+      return { ...p, ...patch };
+    });
     set({ plans });
     saveLocal(plans);
   },