diff --git a/static/app.js b/static/app.js
index a77df40..a6e2791 100644
--- a/static/app.js
+++ b/static/app.js
@@ -13,6 +13,8 @@ const state = {
   history: {},          // { scriptPath: [record, ...] }
   scripts: [],          // 配置中的全部脚本
   autoscroll: true,
+  expandedLogs: new Set(),   // 已展开的历史日志 record ID（re-render 后恢复）
+  lastLiveKey: null,         // 上次渲染的"当前任务身份"（用于判断是否需要重建 DOM）
 };
 
 // ============ Helpers ============
@@ -119,6 +121,7 @@ function renderRunning() {
     stateBadge.className = "badge badge-grey";
     body.innerHTML = `<p class="empty">当前没有任务在执行</p>`;
     sizeEl.textContent = "";
+    state.lastLiveKey = null;
     return;
   }
 
@@ -126,30 +129,49 @@ function renderRunning() {
   stateBadge.textContent = "执行中";
   stateBadge.className = "badge badge-warn";
 
-  body.innerHTML = `
-    <dl class="running-meta">
-      <dt>仓库</dt><dd>${escapeHtml(c.task.repo)}</dd>
-      <dt>分支</dt><dd>${escapeHtml(c.task.ref)}</dd>
-      <dt>Commit</dt><dd>${escapeHtml(shortCommit(c.task.commit))}</dd>
-      <dt>脚本</dt><dd>${escapeHtml(c.task.script)}</dd>
-      <dt>开始</dt><dd>${escapeHtml(fmtFullTime(c.startedAt))}</dd>
-    </dl>
-    <pre class="log-box" id="live-log"></pre>
-  `;
-
-  const logBox = $("#live-log");
+  const liveKey = `${c.task.script}|${c.task.repo}|${c.task.ref}|${c.startedAt}`;
   // 仅渲染尾部以避免长日志卡顿
   const fullLog = c.log || "";
   const tail = fullLog.length > LOG_TAIL_CHARS
     ? fullLog.slice(fullLog.length - LOG_TAIL_CHARS)
     : fullLog;
+
+  if (state.lastLiveKey !== liveKey) {
+    // 任务身份变化:重建结构并贴底
+    body.innerHTML = `
+      <dl class="running-meta">
+        <dt>仓库</dt><dd>${escapeHtml(c.task.repo)}</dd>
+        <dt>分支</dt><dd>${escapeHtml(c.task.ref)}</dd>
+        <dt>Commit</dt><dd>${escapeHtml(shortCommit(c.task.commit))}</dd>
+        <dt>脚本</dt><dd>${escapeHtml(c.task.script)}</dd>
+        <dt>开始</dt><dd>${escapeHtml(fmtFullTime(c.startedAt))}</dd>
+      </dl>
+      <pre class="log-box" id="live-log"></pre>
+    `;
+    state.lastLiveKey = liveKey;
+    const logBox = $("#live-log");
+    logBox.textContent = tail || "（等待脚本输出…）";
+    sizeEl.textContent = fullLog.length
+      ? `${(fullLog.length / 1024).toFixed(1)} KB`
+      : "";
+    requestAnimationFrame(() => {
+      logBox.scrollTop = logBox.scrollHeight;
+    });
+    return;
+  }
+
+  // 同一任务:仅更新日志内容,保持 DOM 节点稳定
+  const logBox = $("#live-log");
+  const distanceFromBottom = logBox.scrollHeight - logBox.scrollTop - logBox.clientHeight;
+  const atBottom = distanceFromBottom <= 24;
   logBox.textContent = tail || "（等待脚本输出…）";
   sizeEl.textContent = fullLog.length
     ? `${(fullLog.length / 1024).toFixed(1)} KB`
     : "";
-
-  if (state.autoscroll) {
-    logBox.scrollTop = logBox.scrollHeight;
+  if (state.autoscroll && atBottom) {
+    requestAnimationFrame(() => {
+      logBox.scrollTop = logBox.scrollHeight;
+    });
   }
 }
 
@@ -195,7 +217,7 @@ function renderHistory() {
               <td>${escapeHtml(r.reason || "")}</td>
               <td>
                 ${r.log
-                  ? `<button class="toggle-log" data-target="${logId}" type="button">查看日志</button>`
+                  ? `<button class="toggle-log" data-target="${logId}" data-id="${r.id}" type="button">查看日志</button>`
                   : `<span class="muted small">无日志</span>`}
               </td>
             </tr>
@@ -225,14 +247,29 @@ function renderHistory() {
     `;
   }).join("");
 
-  // 绑定展开日志按钮
+  // 恢复展开状态（re-render 后保持已展开的日志）
+  root.querySelectorAll(".toggle-log").forEach((btn) => {
+    const expanded = state.expandedLogs.has(btn.dataset.id);
+    btn.textContent = expanded ? "收起日志" : "查看日志";
+    const t = document.getElementById(btn.dataset.target);
+    if (t) t.style.display = expanded ? "block" : "none";
+  });
+
+  // 绑定展开日志按钮（以 state.expandedLogs 为单一事实源）
   root.querySelectorAll(".toggle-log").forEach((btn) => {
     btn.addEventListener("click", () => {
       const target = document.getElementById(btn.dataset.target);
       if (!target) return;
-      const visible = target.style.display !== "none";
-      target.style.display = visible ? "none" : "block";
-      btn.textContent = visible ? "查看日志" : "收起日志";
+      const id = btn.dataset.id;
+      if (state.expandedLogs.has(id)) {
+        state.expandedLogs.delete(id);
+        target.style.display = "none";
+        btn.textContent = "查看日志";
+      } else {
+        state.expandedLogs.add(id);
+        target.style.display = "block";
+        btn.textContent = "收起日志";
+      }
     });
   });
 }
@@ -246,6 +283,14 @@ $("#refresh-btn").addEventListener("click", () => {
 $("#log-autoscroll").addEventListener("click", (e) => {
   state.autoscroll = !state.autoscroll;
   e.currentTarget.classList.toggle("active", state.autoscroll);
+  if (state.autoscroll) {
+    const logBox = $("#live-log");
+    if (logBox) {
+      requestAnimationFrame(() => {
+        logBox.scrollTop = logBox.scrollHeight;
+      });
+    }
+  }
 });
 
 pollQueue();