diff --git a/x2paddle/op_mapper/onnx_opsets/opset9.py b/x2paddle/op_mapper/onnx_opsets/opset9.py
index 5cf058f58ed3c35f54ff26cec469739cded0a23c..931900b2d7949725cedc3b91086e9b10c4c8413a 100644
--- a/x2paddle/op_mapper/onnx_opsets/opset9.py
+++ b/x2paddle/op_mapper/onnx_opsets/opset9.py
@@ -107,6 +107,10 @@ class OpSet9():
             'reduce_min', ['X'], ['Out'], dict(
                 axes='dim', keepdims='keep_dim'), dict(keep_dim=1)
         ],
+        'ReduceMax': [
+            'reduce_max', ['X'], ['Out'], dict(
+                axes='dim', keepdims='keep_dim'), dict(keep_dim=1)
+        ],
         #active function
         'Relu': ['relu', ['X'], ['Out']],
         'LeakyRelu': ['leaky_relu', ['X'], ['Out'], dict(), dict(alpha=.01)],
@@ -131,10 +135,7 @@ class OpSet9():
         'Abs': ['abs', ['X'], ['Out']],
     }
 
-    default_ioa_constraint = {
-        'Gather':
-        [(lambda i, o, a: a.get('axis', 0) == 0, 'only axis = 0 is supported')],
-    }
+    default_ioa_constraint = {}
 
     def __init__(self, decoder):
         super(OpSet9, self).__init__()
@@ -1082,6 +1083,17 @@ class OpSet9():
             output=node,
             param_attr=None)
 
+    @print_mapping_info
+    def Greater(self, node):
+        val_x = self.graph.get_input_node(node, idx=0, copy=True)
+        val_y = self.graph.get_input_node(node, idx=1, copy=True)
+        node.fluid_code.add_layer(
+            "greater_than",
+            inputs={'x': val_x,
+                    'y': val_y},
+            output=node,
+            param_attr=None)
+
     @print_mapping_info
     def Where(self, node):
         condition = self.graph.get_input_node(node, idx=0, copy=True)