diff --git a/mindspore/nn/probability/distribution/_utils/custom_ops.py b/mindspore/nn/probability/distribution/_utils/custom_ops.py
index 430a311613..e8acac6a07 100644
--- a/mindspore/nn/probability/distribution/_utils/custom_ops.py
+++ b/mindspore/nn/probability/distribution/_utils/custom_ops.py
@@ -15,24 +15,30 @@
 """Utitly functions to help distribution class."""
 import numpy as np
 from mindspore.ops import operations as P
+from mindspore.common import dtype as mstype
 
 def log_by_step(input_x):
     """
     Log op on Ascend is calculated as log(abs(x)).
     Fix this with putting negative values as nan.
     """
-    select = P.Select()
     log = P.Log()
+    less = P.Less()
     lessequal = P.LessEqual()
     fill = P.Fill()
+    cast = P.Cast()
     dtype = P.DType()
     shape = P.Shape()
+    select = P.Select()
 
+    input_x = cast(input_x, mstype.float32)
+    nan = fill(dtype(input_x), shape(input_x), np.nan)
+    inf = fill(dtype(input_x), shape(input_x), np.inf)
+    neg_x = less(input_x, 0.0)
     nonpos_x = lessequal(input_x, 0.0)
     log_x = log(input_x)
-    nan = fill(dtype(input_x), shape(input_x), np.nan)
-    result = select(nonpos_x, nan, log_x)
-    return result
+    result = select(nonpos_x, -inf, log_x)
+    return select(neg_x, nan, result)
 
 def log1p_by_step(x):
     """
diff --git a/tests/ut/python/nn/distribution/test_bernoulli.py b/tests/ut/python/nn/distribution/test_bernoulli.py
index e04438f0a9..29fe10a844 100644
--- a/tests/ut/python/nn/distribution/test_bernoulli.py
+++ b/tests/ut/python/nn/distribution/test_bernoulli.py
@@ -157,51 +157,127 @@ def test_cross_entropy():
     ans = net(probs_b, probs_a)
     assert isinstance(ans, Tensor)
 
-class BernoulliBasics(nn.Cell):
+class BernoulliConstruct(nn.Cell):
+    """
+    Bernoulli distribution: going through construct.
+    """
+    def __init__(self):
+        super(BernoulliConstruct, self).__init__()
+        self.b = msd.Bernoulli(0.5, dtype=dtype.int32)
+        self.b1 = msd.Bernoulli(dtype=dtype.int32)
+
+    def construct(self, value, probs):
+        prob = self.b('prob', value)
+        prob1 = self.b('prob', value, probs)
+        prob2 = self.b1('prob', value, probs)
+        return prob + prob1 + prob2
+
+def test_bernoulli_construct():
+    """
+    Test probability function going through construct.
+    """
+    net = BernoulliConstruct()
+    value = Tensor([0, 0, 0, 0, 0], dtype=dtype.float32)
+    probs = Tensor([0.5], dtype=dtype.float32)
+    ans = net(value, probs)
+    assert isinstance(ans, Tensor)
+
+class BernoulliMean(nn.Cell):
     """
     Test class: basic mean/sd/var/mode/entropy function.
     """
     def __init__(self):
-        super(BernoulliBasics, self).__init__()
+        super(BernoulliMean, self).__init__()
         self.b = msd.Bernoulli([0.3, 0.5], dtype=dtype.int32)
 
     def construct(self):
         mean = self.b.mean()
+        return mean
+
+def test_mean():
+    """
+    Test mean/sd/var/mode/entropy functionality of Bernoulli distribution.
+    """
+    net = BernoulliMean()
+    ans = net()
+    assert isinstance(ans, Tensor)
+
+class BernoulliSd(nn.Cell):
+    """
+    Test class: basic mean/sd/var/mode/entropy function.
+    """
+    def __init__(self):
+        super(BernoulliSd, self).__init__()
+        self.b = msd.Bernoulli([0.3, 0.5], dtype=dtype.int32)
+
+    def construct(self):
         sd = self.b.sd()
+        return sd
+
+def test_sd():
+    """
+    Test mean/sd/var/mode/entropy functionality of Bernoulli distribution.
+    """
+    net = BernoulliSd()
+    ans = net()
+    assert isinstance(ans, Tensor)
+
+class BernoulliVar(nn.Cell):
+    """
+    Test class: basic mean/sd/var/mode/entropy function.
+    """
+    def __init__(self):
+        super(BernoulliVar, self).__init__()
+        self.b = msd.Bernoulli([0.3, 0.5], dtype=dtype.int32)
+
+    def construct(self):
         var = self.b.var()
+        return var
+
+def test_var():
+    """
+    Test mean/sd/var/mode/entropy functionality of Bernoulli distribution.
+    """
+    net = BernoulliVar()
+    ans = net()
+    assert isinstance(ans, Tensor)
+
+class BernoulliMode(nn.Cell):
+    """
+    Test class: basic mean/sd/var/mode/entropy function.
+    """
+    def __init__(self):
+        super(BernoulliMode, self).__init__()
+        self.b = msd.Bernoulli([0.3, 0.5], dtype=dtype.int32)
+
+    def construct(self):
         mode = self.b.mode()
-        entropy = self.b.entropy()
-        return mean + sd + var + mode + entropy
+        return mode
 
-def test_bascis():
+def test_mode():
     """
     Test mean/sd/var/mode/entropy functionality of Bernoulli distribution.
     """
-    net = BernoulliBasics()
+    net = BernoulliMode()
     ans = net()
     assert isinstance(ans, Tensor)
 
-class BernoulliConstruct(nn.Cell):
+class BernoulliEntropy(nn.Cell):
     """
-    Bernoulli distribution: going through construct.
+    Test class: basic mean/sd/var/mode/entropy function.
     """
     def __init__(self):
-        super(BernoulliConstruct, self).__init__()
-        self.b = msd.Bernoulli(0.5, dtype=dtype.int32)
-        self.b1 = msd.Bernoulli(dtype=dtype.int32)
+        super(BernoulliEntropy, self).__init__()
+        self.b = msd.Bernoulli([0.3, 0.5], dtype=dtype.int32)
 
-    def construct(self, value, probs):
-        prob = self.b('prob', value)
-        prob1 = self.b('prob', value, probs)
-        prob2 = self.b1('prob', value, probs)
-        return prob + prob1 + prob2
+    def construct(self):
+        entropy = self.b.entropy()
+        return entropy
 
-def test_bernoulli_construct():
+def test_entropy():
     """
-    Test probability function going through construct.
+    Test mean/sd/var/mode/entropy functionality of Bernoulli distribution.
     """
-    net = BernoulliConstruct()
-    value = Tensor([0, 0, 0, 0, 0], dtype=dtype.float32)
-    probs = Tensor([0.5], dtype=dtype.float32)
-    ans = net(value, probs)
+    net = BernoulliEntropy()
+    ans = net()
     assert isinstance(ans, Tensor)