diff --git a/airtest/core/android/adb.py b/airtest/core/android/adb.py
index fbd3e4a0..99441d2e 100644
--- a/airtest/core/android/adb.py
+++ b/airtest/core/android/adb.py
@@ -1059,18 +1059,17 @@ def is_screenon(self):
             True or False whether the screen is turned on or off
 
         """
-        try:
-            screenOnRE = re.compile('mScreenOnFully=(true|false)')
-            m = screenOnRE.search(self.shell('dumpsys window policy'))
-            if m:
-                return (m.group(1) == 'true')
-            raise AirtestError("Couldn't determine screen ON state")
-        except Exception:
+        screenOnRE = re.compile('mScreenOnFully=(true|false)')
+        m = screenOnRE.search(self.shell('dumpsys window policy'))
+        if m:
+            return m.group(1) == 'true'
+        else:
+            # MIUI11
             screenOnRE = re.compile('screenState=(SCREEN_STATE_ON|SCREEN_STATE_OFF)')
             m = screenOnRE.search(self.shell('dumpsys window policy'))
             if m:
-                return (m.group(1) == 'SCREEN_STATE_ON')
-            raise AirtestError("Couldn't determine screen ON state")
+                return m.group(1) == 'SCREEN_STATE_ON'
+        raise AirtestError("Couldn't determine screen ON state")
 
     def is_locked(self):
         """