diff --git a/frontend/src/layouts/MainLayout.tsx b/frontend/src/layouts/MainLayout.tsx
index 2cc7268..15aa99a 100644
--- a/frontend/src/layouts/MainLayout.tsx
+++ b/frontend/src/layouts/MainLayout.tsx
@@ -170,8 +170,29 @@ function getInitialOpenKeys(sections: SidebarSection[], selectedKey: string) {
     .map((section) => section.key)
 }
 
+const SIDEBAR_OPEN_KEYS_KEY = 'sidebar_open_keys'
+const SIDEBAR_COLLAPSED_KEY = 'sidebar_collapsed'
+
+function loadStoredOpenKeys(sections: SidebarSection[], selectedKey: string): string[] {
+  const initial = getInitialOpenKeys(sections, selectedKey)
+  try {
+    const raw = localStorage.getItem(SIDEBAR_OPEN_KEYS_KEY)
+    if (raw) {
+      const parsed = JSON.parse(raw)
+      if (Array.isArray(parsed)) {
+        return Array.from(new Set([...parsed, ...initial]))
+      }
+    }
+  } catch (e) {
+    // ignore
+  }
+  return initial
+}
+
 export default function MainLayout() {
-  const [collapsed, setCollapsed] = useState(false)
+  const [collapsed, setCollapsed] = useState<boolean>(() => {
+    return localStorage.getItem(SIDEBAR_COLLAPSED_KEY) === 'true'
+  })
   const { user, logout, isAdmin } = useAuth()
   const navigate = useNavigate()
   const location = useLocation()
@@ -179,11 +200,15 @@ export default function MainLayout() {
 
   const sections = useMemo(() => (isAdmin ? adminSections : merchantSections), [isAdmin])
   const selectedKey = getSelectedKey(location.pathname, location.search)
-  const [openKeys, setOpenKeys] = useState<string[]>(() => getInitialOpenKeys(sections, selectedKey))
+  const [openKeys, setOpenKeys] = useState<string[]>(() => loadStoredOpenKeys(sections, selectedKey))
 
   useEffect(() => {
     const nextOpenKeys = getInitialOpenKeys(sections, selectedKey)
-    setOpenKeys((current) => Array.from(new Set([...current, ...nextOpenKeys])))
+    setOpenKeys((current) => {
+      const merged = Array.from(new Set([...current, ...nextOpenKeys]))
+      localStorage.setItem(SIDEBAR_OPEN_KEYS_KEY, JSON.stringify(merged))
+      return merged
+    })
   }, [sections, selectedKey])
 
   const toggleSection = (section: SidebarSection) => {
@@ -197,11 +222,18 @@ export default function MainLayout() {
       if (firstEnabledChild?.path) navigate(firstEnabledChild.path)
       return
     }
-    setOpenKeys((current) =>
-      current.includes(section.key)
+    setOpenKeys((current) => {
+      const next = current.includes(section.key)
         ? current.filter((key) => key !== section.key)
-        : [...current, section.key],
-    )
+        : [...current, section.key]
+      localStorage.setItem(SIDEBAR_OPEN_KEYS_KEY, JSON.stringify(next))
+      return next
+    })
+  }
+
+  const handleToggleCollapse = (next: boolean) => {
+    setCollapsed(next)
+    localStorage.setItem(SIDEBAR_COLLAPSED_KEY, String(next))
   }
 
   const handleChildClick = (child: SidebarChild) => {
@@ -300,7 +332,7 @@ export default function MainLayout() {
             <button
               className="app-header__collapse"
               type="button"
-              onClick={() => setCollapsed(!collapsed)}
+              onClick={() => handleToggleCollapse(!collapsed)}
               aria-label={collapsed ? '展开侧边栏' : '收起侧边栏'}
               title={collapsed ? '展开侧边栏' : '收起侧边栏'}
             >