diff --git a/src/pass/infer_shape_type.cc b/src/pass/infer_shape_type.cc
index a6903ba8b2d5..0332532717e6 100644
--- a/src/pass/infer_shape_type.cc
+++ b/src/pass/infer_shape_type.cc
@@ -108,7 +108,7 @@ Graph InferAttr(Graph &&ret,
           uint32_t eid = idx.entry_id(nid, igrad[i].index);
           if (fis_none(rshape[eid])) {
             rshape[eid] = rshape[idx.entry_id(fnode.inputs[i])];
-          } else {
+          } else if (!fis_none(rshape[idx.entry_id(fnode.inputs[i])])) {
             CHECK_EQ(rshape[eid], rshape[idx.entry_id(fnode.inputs[i])])
                 << "Backward shape inconsistent with the forward shape";
           }