diff --git a/mindspore/_extends/graph_kernel/model/graph_split.py b/mindspore/_extends/graph_kernel/model/graph_split.py
index 665c0b98ff..82c8d8e322 100644
--- a/mindspore/_extends/graph_kernel/model/graph_split.py
+++ b/mindspore/_extends/graph_kernel/model/graph_split.py
@@ -488,7 +488,7 @@ class GraphSplitGpu(GraphSplitByPattern):
                     stitch_tensors = [tensor for tensor in dom_outs if tensor in a_ins]
                     if _same_stitch_axis(stitch_tensors, a_final_outs):
                         for tensor in stitch_tensors:
-                            if _tensor_size(tensor) >= 1024 * 1024 * 12:
+                            if _tensor_size(tensor) >= 1024 * 1024:
                                 return True
             return False
 
diff --git a/tests/st/ops/graph_kernel/test_dropoutgrad_reducesum_stitch.py b/tests/st/ops/graph_kernel/test_dropoutgrad_reducesum_stitch.py
new file mode 100644
index 0000000000..3dbc83bc5a
--- /dev/null
+++ b/tests/st/ops/graph_kernel/test_dropoutgrad_reducesum_stitch.py
@@ -0,0 +1,89 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+
+import numpy as np
+import mindspore.context as context
+from mindspore import Tensor
+from mindspore.nn import Cell
+from mindspore.ops import operations as P
+from mindspore.ops.operations import _grad_ops as GP
+from mindspore.common import dtype as mstype
+import pytest
+
+context.set_context(mode=context.GRAPH_MODE, device_target="GPU")
+# enable graph kernel optimization.
+context.set_context(enable_graph_kernel=True)
+
+
+class BertAttentionGradPiece(Cell):
+    def __init__(self):
+        super(BertAttentionGradPiece, self).__init__()
+        self.add = P.Add()
+        self.reducesum = P.ReduceSum(keep_dims=True)
+        self.dropout_grad = GP.DropoutGrad(1 - 0.1)
+        self.sub = P.Sub()
+        self.multiply = P.Mul()
+        self.cast = P.Cast()
+
+    def construct(self, x, y, z):
+        out1 = self.dropout_grad(x, y)
+        out2 = self.multiply(out1, z)
+        out3 = self.reducesum(self.cast(out2, mstype.float32), (-1,))
+        out4 = self.sub(out1, self.cast(out3, mstype.float16))
+        return out4
+
+
+def get_rtol_atol(dtype):
+    if dtype == np.float16:
+        return 1.e-3, 1.e-3
+    return 1.e-4, 1.e-4
+
+
+def compare_result(expect, output, dtype):
+    rtol, atol = get_rtol_atol(dtype)
+    if isinstance(expect, (list, tuple)):
+        assert isinstance(output, (list, tuple)) and len(expect) == len(output)
+        expect_list = list(expect)
+        output_list = list(output)
+        for e, o in zip(expect_list, output_list):
+            assert np.allclose(e.asnumpy(), o.asnumpy(), rtol, atol, equal_nan=True)
+    else:
+        assert np.allclose(expect.asnumpy(), output.asnumpy(), rtol, atol, equal_nan=True)
+
+
+def get_dropoutgrad_reducesum_output(x, y, z, enable_stitch_fusion):
+    # enable graph kernel stitch fusion.
+    if enable_stitch_fusion:
+        context.set_context(graph_kernel_flags="--enable_stitch_fusion=true")
+    net = BertAttentionGradPiece()
+    result = net(x, y, z)
+    return result
+
+
+def test_dropoutgrad_reducesum(shape, dtype):
+    x = Tensor(np.random.normal(0, 1, shape).astype(dtype))
+    y = Tensor(np.random.normal(0, 1, shape).astype(dtype))
+    z = Tensor(np.random.normal(0, 1, shape).astype(dtype))
+    expect = get_dropoutgrad_reducesum_output(x, y, z, False)
+    output = get_dropoutgrad_reducesum_output(x, y, z, True)
+    compare_result(expect, output, dtype)
+
+
+@pytest.mark.level0
+@pytest.mark.platform_x86_gpu_training
+@pytest.mark.env_onecard
+def test_dropoutgrad_reducesum_gpu():
+    context.set_context(mode=context.GRAPH_MODE, device_target="GPU")
+    test_dropoutgrad_reducesum([64, 12, 128, 128], np.float16)
diff --git a/tests/st/ops/graph_kernel/test_layernorm_stitch.py b/tests/st/ops/graph_kernel/test_layernorm_stitch.py
new file mode 100644
index 0000000000..542b307a0f
--- /dev/null
+++ b/tests/st/ops/graph_kernel/test_layernorm_stitch.py
@@ -0,0 +1,86 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+
+import numpy as np
+import mindspore.context as context
+from mindspore import Tensor
+import mindspore.nn as nn
+from mindspore.nn import Cell
+from mindspore.ops import operations as P
+import pytest
+
+context.set_context(mode=context.GRAPH_MODE, device_target="GPU")
+# enable graph kernel optimization.
+context.set_context(enable_graph_kernel=True)
+
+
+class EmbeddingPostprocessor(Cell):
+    def __init__(self):
+        super(EmbeddingPostprocessor, self).__init__()
+        self.layernorm = nn.LayerNorm((768,))
+        self.add = P.Add()
+        self.dropout = nn.Dropout(1 - 0.1)
+
+    def construct(self, word_embeddings, token_type_embeddings, position_embeddings):
+        output = word_embeddings
+        output = self.add(output, token_type_embeddings)
+        output = self.add(output, position_embeddings)
+        output = self.layernorm(output)
+        output = self.dropout(output)
+        return output
+
+
+def get_rtol_atol(dtype):
+    if dtype == np.float16:
+        return 1.e-3, 1.e-3
+    return 1.e-4, 1.e-4
+
+
+def compare_result(expect, output, dtype):
+    rtol, atol = get_rtol_atol(dtype)
+    if isinstance(expect, (list, tuple)):
+        assert isinstance(output, (list, tuple)) and len(expect) == len(output)
+        expect_list = list(expect)
+        output_list = list(output)
+        for e, o in zip(expect_list, output_list):
+            assert np.allclose(e.asnumpy(), o.asnumpy(), rtol, atol, equal_nan=True)
+    else:
+        assert np.allclose(expect.asnumpy(), output.asnumpy(), rtol, atol, equal_nan=True)
+
+
+def get_layernorm_output(x, y, z, enable_stitch_fusion):
+    # enable graph kernel stitch fusion.
+    if enable_stitch_fusion:
+        context.set_context(graph_kernel_flags="--enable_stitch_fusion=true")
+    net = EmbeddingPostprocessor()
+    result = net(x, y, z)
+    return result
+
+
+def test_layernorm(shape1, shape2, dtype):
+    x = Tensor(np.random.normal(0, 1, shape1).astype(dtype))
+    y = Tensor(np.random.normal(0, 1, shape1).astype(dtype))
+    z = Tensor(np.random.normal(0, 1, shape2).astype(dtype))
+    expect = get_layernorm_output(x, y, z, False)
+    output = get_layernorm_output(x, y, z, True)
+    compare_result(expect, output, dtype)
+
+
+@pytest.mark.level0
+@pytest.mark.platform_x86_gpu_training
+@pytest.mark.env_onecard
+def test_layernorm_gpu():
+    context.set_context(mode=context.GRAPH_MODE, device_target="GPU")
+    test_layernorm([8192, 768], [1, 768], np.float32)
diff --git a/tests/st/ops/graph_kernel/test_softmax_stitch.py b/tests/st/ops/graph_kernel/test_softmax_stitch.py
new file mode 100644
index 0000000000..49994ca6e4
--- /dev/null
+++ b/tests/st/ops/graph_kernel/test_softmax_stitch.py
@@ -0,0 +1,92 @@
+# Copyright 2021 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ============================================================================
+
+import numpy as np
+import mindspore.context as context
+from mindspore import Tensor
+import mindspore.nn as nn
+from mindspore.nn import Cell
+from mindspore.ops import operations as P
+import mindspore.ops.functional as F
+import pytest
+
+context.set_context(mode=context.GRAPH_MODE, device_target="GPU")
+# enable graph kernel optimization.
+context.set_context(enable_graph_kernel=True)
+
+
+class BertAttentionPiece(Cell):
+    def __init__(self):
+        super(BertAttentionPiece, self).__init__()
+        self.add = P.Add()
+        self.dropout = nn.Dropout(1 - 0.1)
+        self.softmax = nn.Softmax()
+        self.multiply_data = -10000.0
+        self.sub = P.Sub()
+        self.multiply = P.Mul()
+        self.get_dtype = P.DType()
+        self.cast = P.Cast()
+
+    def construct(self, attention_mask, attention_scores):
+        multiply_out = self.sub(self.cast(F.tuple_to_array((1.0,)), self.get_dtype(attention_scores)),
+                                self.cast(attention_mask, self.get_dtype(attention_scores)))
+        adder = self.multiply(multiply_out, self.multiply_data)
+        attention_scores = self.add(adder, attention_scores)
+        attention_probs = self.softmax(attention_scores)
+        attention_probs = self.dropout(attention_probs)
+        return attention_probs
+
+
+def get_rtol_atol(dtype):
+    if dtype == np.float16:
+        return 1.e-3, 1.e-3
+    return 1.e-4, 1.e-4
+
+
+def compare_result(expect, output, dtype):
+    rtol, atol = get_rtol_atol(dtype)
+    if isinstance(expect, (list, tuple)):
+        assert isinstance(output, (list, tuple)) and len(expect) == len(output)
+        expect_list = list(expect)
+        output_list = list(output)
+        for e, o in zip(expect_list, output_list):
+            assert np.allclose(e.asnumpy(), o.asnumpy(), rtol, atol, equal_nan=True)
+    else:
+        assert np.allclose(expect.asnumpy(), output.asnumpy(), rtol, atol, equal_nan=True)
+
+
+def get_softmax_output(x, y, enable_stitch_fusion):
+    # enable graph kernel stitch fusion.
+    if enable_stitch_fusion:
+        context.set_context(graph_kernel_flags="--enable_stitch_fusion=true")
+    net = BertAttentionPiece()
+    result = net(x, y)
+    return result
+
+
+def test_softmax(shape, dtype):
+    x = Tensor(np.random.normal(0, 1, shape).astype(dtype))
+    y = Tensor(np.random.normal(0, 1, shape).astype(dtype))
+    expect = get_softmax_output(x, y, False)
+    output = get_softmax_output(x, y, True)
+    compare_result(expect, output, dtype)
+
+
+@pytest.mark.level0
+@pytest.mark.platform_x86_gpu_training
+@pytest.mark.env_onecard
+def test_softmax_gpu():
+    context.set_context(mode=context.GRAPH_MODE, device_target="GPU")
+    test_softmax([64, 12, 128, 128], np.float16)