diff --git a/cmd/safesightd/main.go b/cmd/safesightd/main.go
index 05fe142..f835b2b 100644
--- a/cmd/safesightd/main.go
+++ b/cmd/safesightd/main.go
@@ -6,7 +6,6 @@ import (
     "net/http"
     "os"
     "path/filepath"
-    "strconv"
 
 	"safesight-control/internal/api"
 	"safesight-control/internal/config"
@@ -76,14 +75,7 @@ func main() {
         log.Printf("load persisted tasks: %v", err)
     }
     alarmCollector := service.NewAlarmCollector(store.DB(), agentClient, regSvc)
-    // Load retention from DB (UI-persisted), fallback to config file
-    retention := cfg.AlarmRetentionDays
-    if persisted, err := storage.LoadSetting(store.DB(), "alarm_retention_days"); err == nil && persisted != "" {
-        if v, err := strconv.Atoi(persisted); err == nil && v >= 0 {
-            retention = v
-        }
-    }
-    alarmCollector.SetRetention(retention)
+    alarmCollector.SetRetention(cfg.AlarmRetentionDays)
     alarmCollector.Start()
     tplSvc := service.NewTemplateService(cfg)
     h := api.NewHandler(discoSvc, regSvc, agentClient, taskSvc, tplSvc)
@@ -114,6 +106,7 @@ func main() {
     ui.SetStateRepo(stateRepo)
     ui.SetAuditRepo(auditRepo)
     ui.SetDBPath(cfg.DBPathOrDefault())
+    ui.SetConfig(cfg, cfgPath)
     ui.SetResourcesRepo(resourcesRepo)
     ui.SetAlarmCollector(alarmCollector)
     autoCfgSvc := service.NewAutoConfigService(previewSvc, taskSvc, service.NewFeatureRegistry())
diff --git a/internal/storage/migrate.go b/internal/storage/migrate.go
index 19ffd3e..5b6ae87 100644
--- a/internal/storage/migrate.go
+++ b/internal/storage/migrate.go
@@ -480,10 +480,6 @@ CREATE TABLE IF NOT EXISTS config_versions (
   config_id TEXT NOT NULL DEFAULT '',
   config_json TEXT NOT NULL,
   created_at TEXT NOT NULL
-);
-CREATE TABLE IF NOT EXISTS settings (
-  key TEXT PRIMARY KEY,
-  value TEXT NOT NULL DEFAULT ''
 )
 `)
     return err
diff --git a/internal/storage/settings.go b/internal/storage/settings.go
deleted file mode 100644
index 2efeb63..0000000
--- a/internal/storage/settings.go
+++ /dev/null
@@ -1,15 +0,0 @@
-package storage
-
-import "database/sql"
-
-func LoadSetting(db *sql.DB, key string) (string, error) {
-    if db == nil {
-        return "", nil
-    }
-    var value string
-    err := db.QueryRow("SELECT value FROM settings WHERE key = ?", key).Scan(&value)
-    if err == sql.ErrNoRows {
-        return "", nil
-    }
-    return value, err
-}
diff --git a/internal/web/ui.go b/internal/web/ui.go
index 53a8305..b7417cb 100644
--- a/internal/web/ui.go
+++ b/internal/web/ui.go
@@ -23,6 +23,7 @@ import (
     "time"
     "unicode/utf8"
 
+	"safesight-control/internal/config"
 	"safesight-control/internal/models"
 	"safesight-control/internal/service"
 	"safesight-control/internal/storage"
@@ -40,6 +41,8 @@ type UI struct {
     stateRepo *storage.DeviceConfigStateRepo
     auditRepo *storage.AuditLogsRepo
     dbPath    string
+    configPath string
+    cfg       *config.Config
     resourcesRepo *storage.ResourcesRepo
     alarmCollector *service.AlarmCollector
     autoConfig        *service.AutoConfigService
@@ -641,6 +644,14 @@ func (u *UI) SetDBPath(path string) {
     u.dbPath = strings.TrimSpace(path)
 }
 
+func (u *UI) SetConfig(cfg *config.Config, cfgPath string) {
+    if u == nil {
+        return
+    }
+    u.cfg = cfg
+    u.configPath = cfgPath
+}
+
 func (u *UI) SetResourcesRepo(repo *storage.ResourcesRepo) {
     if u == nil {
         return
@@ -4270,8 +4281,8 @@ func (u *UI) renderSystemPage(w http.ResponseWriter, r *http.Request, status int
         SystemAlarmRetention: 30,
         SystemConcurrency:    5,
     }
-    if u.alarmCollector != nil {
-        data.SystemAlarmRetention = u.alarmCollector.GetRetention()
+    if u.cfg != nil {
+        data.SystemAlarmRetention = u.cfg.AlarmRetentionDays
     }
     u.render(w, r, "system", data)
 }
@@ -4283,16 +4294,16 @@ func (u *UI) actionSystemConfig(w http.ResponseWriter, r *http.Request) {
             u.alarmCollector.SetRetention(days)
             go u.alarmCollector.RunCleanup()
         }
-        // Persist to DB so it survives restart
-        if strings.TrimSpace(u.dbPath) != "" {
-            if store, err := storage.OpenSQLite(u.dbPath); err == nil {
-                store.DB().Exec("INSERT OR REPLACE INTO settings(key,value) VALUES('alarm_retention_days',?)", strconv.Itoa(days))
-                store.Close()
+        // Write back to config file
+        if u.cfg != nil && strings.TrimSpace(u.configPath) != "" {
+            u.cfg.AlarmRetentionDays = days
+            if data, err := json.MarshalIndent(u.cfg, "", "  "); err == nil {
+                os.WriteFile(u.configPath, data, 0o644)
             }
         }
-        msg := "告警保留已设为 " + strconv.Itoa(days) + " 天，已持久化"
+        msg := "告警保留已设为 " + strconv.Itoa(days) + " 天"
         if days == 0 {
-            msg = "告警将永久保留，已持久化"
+            msg = "告警将永久保留"
         }
         u.renderSystemPage(w, r, http.StatusOK, msg, "")
         return
diff --git a/safesightd-linux-arm64 b/safesightd-linux-arm64
index 9be1b35..f8504b7 100644
Binary files a/safesightd-linux-arm64 and b/safesightd-linux-arm64 differ