diff --git a/python/jittor/__init__.py b/python/jittor/__init__.py
index e49cdb8c..57277ad6 100644
--- a/python/jittor/__init__.py
+++ b/python/jittor/__init__.py
@@ -113,6 +113,22 @@ Example::
         self.jt_flags = jt_flags
         jt_flags["no_grad"] = 1
 
+class enable_grad(flag_scope):
+    ''' enable_grad scope, all variable created inside this
+scope will start grad.
+
+Example::
+
+    import jittor as jt
+
+    with jt.enable_grad():
+        ...
+
+    '''
+    def __init__(self, **jt_flags):
+        self.jt_flags = jt_flags
+        jt_flags["no_grad"] = 0
+
 single_log_capture = None
 
 class log_capture_scope(_call_no_record_scope):