diff --git a/python/xorbits/_mars/dataframe/groupby/aggregation.py b/python/xorbits/_mars/dataframe/groupby/aggregation.py
index 1d038944b..1363831ae 100644
--- a/python/xorbits/_mars/dataframe/groupby/aggregation.py
+++ b/python/xorbits/_mars/dataframe/groupby/aggregation.py
@@ -1186,6 +1186,13 @@ def _execute_combine(cls, ctx, op: "DataFrameGroupByAgg"):
                 combines.append(
                     cls._do_predefined_agg(input_obj, agg_func_name, gpu=op.gpu, **kwds)
                 )
+        for i, combine in enumerate(combines):
+            if (
+                isinstance(combine.index, xdf.MultiIndex)
+                and op.groupby_params["sort"] is True
+                and not combine.index.is_monotonic_increasing
+            ):
+                combines[i] = combine.sort_index()
         ctx[op.outputs[0].key] = tuple(combines)
 
     @classmethod