diff --git a/src/__tests__/composables/fragment.spec.ts b/src/__tests__/composables/fragment.spec.ts
index efc1e9e..d410dcb 100644
--- a/src/__tests__/composables/fragment.spec.ts
+++ b/src/__tests__/composables/fragment.spec.ts
@@ -88,4 +88,25 @@ describe('useStudyFragment', () => {
     expect(result).toBe(false)
     expect(ElMessage.error).toHaveBeenCalledWith('网络超时')
   })
+
+  it('prevents duplicate submission while creating fragment', async () => {
+    let resolveCreate!: (value: any) => void
+    vi.mocked(createFragments).mockImplementation(
+      () => new Promise((resolve) => { resolveCreate = resolve }),
+    )
+    const { fragmentContent, creatingFragment, confirmGenerateFragment } = useStudyFragment()
+    fragmentContent.value = '学习内容'
+
+    const first = confirmGenerateFragment('S001')
+    const second = confirmGenerateFragment('S001')
+    await Promise.resolve()
+
+    expect(createFragments).toHaveBeenCalledTimes(1)
+    expect(creatingFragment.value).toBe(true)
+
+    resolveCreate({ code: 200 })
+    await Promise.all([first, second])
+
+    expect(creatingFragment.value).toBe(false)
+  })
 })
diff --git a/src/components/StartTask.vue b/src/components/StartTask.vue
index af5d3b5..99985d1 100644
--- a/src/components/StartTask.vue
+++ b/src/components/StartTask.vue
@@ -25,9 +25,12 @@ const {
   openFragmentDialog,
   closeFragmentDialog,
   confirmGenerateFragment,
+  creatingFragment,
 } = useStudyFragment();
 
 const pageLoading = ref(true);
+const timerActionLoading = ref(false);
+const endingSession = ref(false);
 
 const summaryDialogVisible = ref(false);
 const summaryContent = ref("");
@@ -309,39 +312,51 @@ const statusText = computed(() => {
 });
 
 const startTimer = async () => {
-  if (taskInfo.value.sessionState === "PAUSED") {
-    const res = await continueSession(taskInfo.value.sessionNum);
-    if (res.code === 200) ElMessage.success("任务继续");
-    await loadTaskSession();
+  if (timerActionLoading.value) return;
+  timerActionLoading.value = true;
+  try {
+    if (taskInfo.value.sessionState === "PAUSED") {
+      const res = await continueSession(taskInfo.value.sessionNum);
+      if (res.code === 200) ElMessage.success("任务继续");
+      await loadTaskSession();
+    }
+    // 手动开始 → 清除休息状态
+    localStorage.removeItem(BREAK_END_KEY.value);
+    isBreak.value = false;
+    const duration = taskInfo.value.pointerPosition || 25 * 60 * 1000;
+    runCountdown(duration);
+  } finally {
+    timerActionLoading.value = false;
   }
-  // 手动开始 → 清除休息状态
-  localStorage.removeItem(BREAK_END_KEY.value);
-  isBreak.value = false;
-  const duration = taskInfo.value.pointerPosition || 25 * 60 * 1000;
-  runCountdown(duration);
 };
 
 const stopTimer = async () => {
-  const res = await pauseSession(taskInfo.value.sessionNum);
-  if (res.code === 200) {
-    ElMessage.success("任务暂停");
-    // 重新获取会话数据，同步后端计算后的时间字段
-    try {
-      const detail = await getSessionDetail(taskInfo.value.sessionNum);
-      if (detail?.data) {
-        const d = detail.data;
-        taskInfo.value.sessionState = d.sessionState ?? "PAUSED";
-        taskInfo.value.actualTime = d.actualTime ?? 0;
-        taskInfo.value.effectiveTime = d.effectiveTime ?? 0;
-        taskInfo.value.effectivenessRatio = d.effectivenessRatio ?? 0;
-        taskInfo.value.startTime = d.startTime ?? taskInfo.value.startTime;
-        taskInfo.value.endTime = d.endTime ?? "";
-        taskInfo.value.lastStartTime = d.lastStartTime ?? "";
-        taskInfo.value.pointerPosition = d.pointerPosition ?? 0;
+  if (timerActionLoading.value) return;
+  timerActionLoading.value = true;
+  try {
+    const res = await pauseSession(taskInfo.value.sessionNum);
+    if (res.code === 200) {
+      ElMessage.success("任务暂停");
+      // 重新获取会话数据，同步后端计算后的时间字段
+      try {
+        const detail = await getSessionDetail(taskInfo.value.sessionNum);
+        if (detail?.data) {
+          const d = detail.data;
+          taskInfo.value.sessionState = d.sessionState ?? "PAUSED";
+          taskInfo.value.actualTime = d.actualTime ?? 0;
+          taskInfo.value.effectiveTime = d.effectiveTime ?? 0;
+          taskInfo.value.effectivenessRatio = d.effectivenessRatio ?? 0;
+          taskInfo.value.startTime = d.startTime ?? taskInfo.value.startTime;
+          taskInfo.value.endTime = d.endTime ?? "";
+          taskInfo.value.lastStartTime = d.lastStartTime ?? "";
+          taskInfo.value.pointerPosition = d.pointerPosition ?? 0;
+        }
+      } catch {
+        taskInfo.value.sessionState = "PAUSED";
       }
-    } catch {
-      taskInfo.value.sessionState = "PAUSED";
     }
+  } finally {
+    timerActionLoading.value = false;
   }
   clear();
   clearBreakState();
@@ -367,6 +382,8 @@ const endTimer = async (content: string) => {
     // 用户取消结束会话，不做任何操作
     return;
   }
+  if (endingSession.value) return;
+  endingSession.value = true;
 
   try {
     const res = await endSession(taskInfo.value.sessionNum, content);
@@ -385,6 +402,8 @@ const endTimer = async (content: string) => {
     await router.push("/study");
   } catch {
     ElMessage.error("结束会话失败，请重试");
+  } finally {
+    endingSession.value = false;
   }
 };
 
@@ -741,10 +760,10 @@ defineExpose({
             <el-button @click="openFragmentDialog">生成残片</el-button>
           </template>
           <template v-else>
-            <el-button type="success" @click="startTimer" :disabled="timerRunning">开始</el-button>
-            <el-button @click="stopTimer" :disabled="!timerRunning" v-if="!timerIsOver">暂停</el-button>
+            <el-button type="success" @click="startTimer" :disabled="timerRunning" :loading="timerActionLoading">开始</el-button>
+            <el-button @click="stopTimer" :disabled="!timerRunning" :loading="timerActionLoading" v-if="!timerIsOver">暂停</el-button>
             <el-button @click="openFragmentDialog">生成残片</el-button>
-            <el-button v-if="timerIsOver" plain type="success" @click="restTimer">休息</el-button>
+            <el-button v-if="timerIsOver" plain type="success" @click="restTimer" :loading="timerActionLoading">休息</el-button>
           </template>
           <el-button type="danger" plain @click="openSummaryDialog">结束会话</el-button>
         </div>
@@ -827,7 +846,7 @@ defineExpose({
     />
     <template #footer>
       <el-button @click="closeFragmentDialog">取消</el-button>
-      <el-button type="success" @click="confirmGenerateFragment(taskInfo.sessionNum)">确定生成</el-button>
+      <el-button type="success" :loading="creatingFragment" @click="confirmGenerateFragment(taskInfo.sessionNum)">确定生成</el-button>
     </template>
   </el-dialog>
 
@@ -887,7 +906,7 @@ defineExpose({
     </div>
     <template #footer>
       <el-button @click="closeSummaryDialog">取消</el-button>
-      <el-button type="success" @click="endTimer(summaryContent)">确认结束</el-button>
+      <el-button type="success" :loading="endingSession" @click="endTimer(summaryContent)">确认结束</el-button>
     </template>
   </el-dialog>
   </div>
diff --git a/src/components/composables/fragment.ts b/src/components/composables/fragment.ts
index f9ceea3..7e644de 100644
--- a/src/components/composables/fragment.ts
+++ b/src/components/composables/fragment.ts
@@ -5,6 +5,7 @@ import {createFragments} from '@/api/reportFragments';
 export const useStudyFragment = () => {
     const fragmentsDialogVisible = ref(false);
     const fragmentContent = ref('');
+    const creatingFragment = ref(false);
 
     const openFragmentDialog = () => {
         fragmentContent.value = '';
@@ -26,6 +27,7 @@ export const useStudyFragment = () => {
     };
 
     const confirmGenerateFragment = async (sessionNum: string): Promise<boolean> => {
+        if (creatingFragment.value) return false;
         if (!fragmentContent.value.trim()) {
             ElMessage.warning('请输入学习内容！');
             return false;
@@ -43,6 +45,7 @@ export const useStudyFragment = () => {
         }
 
         try {
+            creatingFragment.value = true;
             const res = await createFragments(sessionNum, fragmentContent.value);
             if (res.code === 200) {
                 ElMessage.success('学习残片生成成功！');
@@ -55,12 +58,15 @@ export const useStudyFragment = () => {
         } catch (error: any) {
             ElMessage.error(error.message || '请求失败');
             return false;
+        } finally {
+            creatingFragment.value = false;
         }
     };
 
     return {
         fragmentsDialogVisible,
         fragmentContent,
+        creatingFragment,
         openFragmentDialog,
         closeFragmentDialog,
         confirmGenerateFragment,