diff --git a/mpmaster/src/main/java/com/xypower/mpmaster/AppMaster.java b/mpmaster/src/main/java/com/xypower/mpmaster/AppMaster.java
index 2999df3d..467065a2 100644
--- a/mpmaster/src/main/java/com/xypower/mpmaster/AppMaster.java
+++ b/mpmaster/src/main/java/com/xypower/mpmaster/AppMaster.java
@@ -319,6 +319,12 @@ public class AppMaster {
             e.printStackTrace();
         }
 
+        try {
+            mService.cleanLogFiles();
+        } catch (Exception ex) {
+            ex.printStackTrace();
+        }
+
         return res;
     }
 
diff --git a/mpmaster/src/main/java/com/xypower/mpmaster/MpMasterService.java b/mpmaster/src/main/java/com/xypower/mpmaster/MpMasterService.java
index 1ce593e4..ce84548a 100644
--- a/mpmaster/src/main/java/com/xypower/mpmaster/MpMasterService.java
+++ b/mpmaster/src/main/java/com/xypower/mpmaster/MpMasterService.java
@@ -101,6 +101,8 @@ public class MpMasterService extends Service {
     private int mQuickHeartbeatDuration = 60; // Unit: second
     private int mHeartbeatDuration = 600; // 10m = 10 * 60s
 
+    private long mTimeForKeepingLogs = 86400000 * 15;   // 15 days
+
     private AlarmReceiver mAlarmReceiver = null;
     private ScreenActionReceiver mScreenaAtionReceiver = null;
     private UpdateReceiver mUpdateReceiver = null;
@@ -164,7 +166,7 @@ public class MpMasterService extends Service {
                 fi.mkdirs();
             }
 
-            File logFile = new File(fi, "log.txt");
+            File logFile = new File(fi, "mlog.txt");
 
             rotatingHandler = new RotatingHandler(logFile.getAbsolutePath(), logFormatter);
 
@@ -242,6 +244,31 @@ public class MpMasterService extends Service {
         }
     }
 
+    public void cleanLogFiles() {
+
+        try {
+            String appPath = MicroPhotoContext.buildMasterAppDir(getApplicationContext());
+            String logPath = appPath + "logs";
+            File fi = new File(logPath);
+            if (!fi.exists()) {
+                return;
+            }
+
+            Date dt = new Date();
+            dt.setHours(0);
+            dt.setMinutes(0);
+            long millis = dt.getTime() - mTimeForKeepingLogs;
+            File[] subFiles = fi.listFiles();
+            for (File f : subFiles) {
+                if (f.lastModified() < millis) {
+                    f.delete();
+                }
+            }
+        } catch (Exception ex) {
+            ex.printStackTrace();
+        }
+    }
+
     @Override
     public void onDestroy() {