diff --git a/frontend/src/components/Step3Simulation.vue b/frontend/src/components/Step3Simulation.vue
index e9dd3dc3..5425cf14 100644
--- a/frontend/src/components/Step3Simulation.vue
+++ b/frontend/src/components/Step3Simulation.vue
@@ -398,7 +398,9 @@ const doStartSimulation = async () => {
     const params = {
       simulation_id: props.simulationId,
       platform: 'parallel',
-      force: true,  // 强制重新开始
+      // 只在确认没有可丢失的运行数据后才会走到这里，因此无需强制重启。
+      // force=true 会让后端删除 actions.jsonl 与 *_simulation.db，绝不能作为隐式默认值。
+      force: false,
       enable_graph_memory_update: true  // 开启动态图谱更新
     }
     
@@ -437,6 +439,62 @@ const doStartSimulation = async () => {
   }
 }
 
+// 判断后端是否已存在不可再生的运行数据
+// run_state 缺失时后端返回 runner_status='idle'，此时才认为是全新的模拟
+const hasRecoverableRun = (status) => {
+  if (!status) return false
+  if (status.runner_status && status.runner_status !== 'idle') return true
+  return (status.total_actions_count || 0) > 0
+}
+
+// 组件挂载入口：先探测后端真实状态，再决定是接管还是新建
+// 页面刷新会重新挂载本组件，直接启动会让后端删除既有的模拟数据
+const resumeOrStartSimulation = async () => {
+  if (!props.simulationId) {
+    addLog(t('log.errorMissingSimId'))
+    return
+  }
+
+  let status = null
+  try {
+    const res = await getRunStatus(props.simulationId)
+    if (!res.success || !res.data) {
+      throw new Error(res.error || t('common.unknownError'))
+    }
+    status = res.data
+  } catch (err) {
+    // 探测失败时保持观望：宁可什么都不做，也不能覆盖可能存在的运行数据
+    startError.value = err.message
+    addLog(t('log.resumeCheckFailed', { error: err.message }))
+    emit('update-status', 'error')
+    return
+  }
+
+  if (!hasRecoverableRun(status)) {
+    await doStartSimulation()
+    return
+  }
+
+  // 已有运行数据：接管现有运行，不重启、不清理
+  runStatus.value = status
+  prevTwitterRound.value = status.twitter_current_round || 0
+  prevRedditRound.value = status.reddit_current_round || 0
+  await fetchRunStatusDetail()
+
+  const isLive = ['starting', 'running', 'paused', 'stopping'].includes(status.runner_status)
+  if (isLive) {
+    phase.value = 1
+    addLog(t('log.resumedRunningSim', { round: status.current_round || 0 }))
+    emit('update-status', 'processing')
+    startStatusPolling()
+    startDetailPolling()
+  } else {
+    phase.value = 2
+    addLog(t('log.loadedExistingSim', { actions: status.total_actions_count || 0 }))
+    emit('update-status', status.runner_status === 'failed' ? 'error' : 'completed')
+  }
+}
+
 // 停止模拟
 const handleStopSimulation = async () => {
   if (!props.simulationId) return
@@ -691,7 +749,7 @@ watch(() => props.systemLogs?.length, () => {
 onMounted(() => {
   addLog(t('log.step3Init'))
   if (props.simulationId) {
-    doStartSimulation()
+    resumeOrStartSimulation()
   }
 })
 
diff --git a/locales/en.json b/locales/en.json
index 02679955..050b9c52 100644
--- a/locales/en.json
+++ b/locales/en.json
@@ -525,6 +525,9 @@
     "loadConfigFailed": "Failed to load config: {error}",
     "step2Init": "Step 2 environment setup initialized",
     "step3Init": "Step 3 simulation run initialized",
+    "resumeCheckFailed": "✗ Could not read run status: {error}. Not starting, to avoid discarding an existing run.",
+    "resumedRunningSim": "↻ Reattached to the running simulation (round {round}) — not restarted",
+    "loadedExistingSim": "↻ Loaded the existing simulation run ({actions} events) — not restarted",
     "startingDualSim": "Starting dual-platform parallel simulation...",
     "setMaxRounds": "Max simulation rounds set to: {rounds}",
     "graphMemoryUpdateEnabled": "Dynamic graph memory update enabled",
diff --git a/locales/zh.json b/locales/zh.json
index c5937dcc..645afa93 100644
--- a/locales/zh.json
+++ b/locales/zh.json
@@ -525,6 +525,9 @@
     "loadConfigFailed": "加载配置失败: {error}",
     "step2Init": "Step2 环境搭建初始化",
     "step3Init": "Step3 模拟运行初始化",
+    "resumeCheckFailed": "✗ 无法获取运行状态: {error}。已跳过启动，避免丢弃已有的模拟数据。",
+    "resumedRunningSim": "↻ 已接管正在运行的模拟（第 {round} 轮）——未重新开始",
+    "loadedExistingSim": "↻ 已载入既有的模拟运行（{actions} 条事件）——未重新开始",
     "startingDualSim": "正在启动双平台并行模拟...",
     "setMaxRounds": "设置最大模拟轮数: {rounds}",
     "graphMemoryUpdateEnabled": "已开启动态图谱更新模式",