diff --git a/mindspore/nn/probability/distribution/_utils/utils.py b/mindspore/nn/probability/distribution/_utils/utils.py
index d49088ad48..5e81d79ae6 100644
--- a/mindspore/nn/probability/distribution/_utils/utils.py
+++ b/mindspore/nn/probability/distribution/_utils/utils.py
@@ -244,8 +244,8 @@ def logits_to_probs(logits, is_binary=False):
         is_binary (bool)
     """
     if is_binary:
-        return nn.sigmoid()(logits)
-    return nn.softmax(axis=-1)(logits)
+        return nn.Sigmoid()(logits)
+    return nn.Softmax(axis=-1)(logits)
 
 
 def clamp_probs(probs):
@@ -300,6 +300,9 @@ def raise_none_error(name):
     raise TypeError(f"the type {name} should be subclass of Tensor."
                     f" It should not be None since it is not specified during initialization.")
 
+@constexpr
+def raise_probs_logits_error():
+    raise TypeError("Either 'probs' or 'logits' must be specified, but not both.")
 
 @constexpr
 def raise_not_impl_error(name):
diff --git a/mindspore/nn/probability/distribution/categorical.py b/mindspore/nn/probability/distribution/categorical.py
index 81b4152e9f..9219841ff7 100644
--- a/mindspore/nn/probability/distribution/categorical.py
+++ b/mindspore/nn/probability/distribution/categorical.py
@@ -17,7 +17,7 @@ import numpy as np
 from mindspore.ops import operations as P
 from mindspore.common import dtype as mstype
 from .distribution import Distribution
-from ._utils.utils import logits_to_probs, probs_to_logits, check_tensor_type, cast_to_tensor
+from ._utils.utils import logits_to_probs, probs_to_logits, check_type, check_tensor_type, cast_to_tensor, raise_probs_logits_error
 
 
 class Categorical(Distribution):
@@ -71,9 +71,11 @@ class Categorical(Distribution):
                  dtype=mstype.int32,
                  name="Categorical"):
         param = dict(locals())
+        valid_dtype = mstype.int_type
+        check_type(dtype, valid_dtype, "Categorical")
         super(Categorical, self).__init__(seed, dtype, name, param)
         if (probs is None) == (logits is None):
-            raise ValueError("Either 'prob' or 'logits' must be specified, but not both.")
+            raise_probs_logits_error()
         self.reduce_sum = P.ReduceSum(keep_dims=True)
         self.log = P.Log()
         self.exp = P.Exp()
@@ -127,8 +129,7 @@ class Categorical(Distribution):
         Returns:
             Tensor, shape is shape(probs)[:-1] + sample_shape
         """
-        if not isinstance(sample_shape, tuple):
-            raise ValueError("sample shape must be a tuple")
+        self.checktuple(sample_shape, 'shape')
         num_sample = 1
         for i in sample_shape:
             num_sample *= i
@@ -136,7 +137,7 @@ class Categorical(Distribution):
         samples = self.mutinomial(probs_2d, num_sample)
         extend_shape = sample_shape
         if len(self.shape(self._probs)) > 1:
-            extend_shape = self.shape(self._probs)[:-1] + sample_shape
+            extend_shape = sample_shape + self.shape(self._probs)[:-1]
         return self.cast(self.reshape(samples, extend_shape), self.dtype)
 
     def _broad_cast_shape(self, a, b):
@@ -183,15 +184,16 @@ class Categorical(Distribution):
         if value is not None:
             check_tensor_type("value", value, [mstype.float32, bool, mstype.int32])
             value = self.expandim(self.cast(value, mstype.float32), -1)
-            broad_shape = self._broad_cast_shape(value, self._logits)
+            index = cast_to_tensor(np.arange(self.shape(value)[0]).astype(np.float32))
+            index = self.expandim(index, -1)
+            logits = self._logits if self._logits.dim() == 1 else self.expandim(self._logits, 0)
+            broad_shape = self._broad_cast_shape(value, logits)
             broad = P.BroadcastTo(broad_shape)
             value = broad(value)[..., :1]
-            index = cast_to_tensor(np.arange(broad_shape[-1]).astype(np.float32))
-            index = self.expandim(index, -1)
             index = broad(index)[..., :1]
             value = self.concat((index, value))
             value = self.cast(value, mstype.int32)
-            return self.gather(self._logits, value)
+            return self.gather(logits, value)
         return None
 
     def _entropy(self):
@@ -209,7 +211,7 @@ class Categorical(Distribution):
        Enumerate categories.
        """
         num_events = self._num_events
-        values = cast_to_tensor(np.arange(num_events).astype(np.int32), mstype.int32)
+        values = cast_to_tensor(np.arange(num_events).astype(np.int32), mstype.float32)
         values = self.reshape(values, (num_events, 1))
         if expand:
             values = P.BroadcastTo((num_events, self._batch_shape))(values)
diff --git a/mindspore/ops/composite/random_ops.py b/mindspore/ops/composite/random_ops.py
index c1d0bf52c9..7ac45d2ed7 100644
--- a/mindspore/ops/composite/random_ops.py
+++ b/mindspore/ops/composite/random_ops.py
@@ -204,14 +204,15 @@ def multinomial(inputs, num_sample, replacement=True, seed=0):
         but must be non-negative, finite and have a non-zero sum.
 
     Args:
-        input (Tensor) - the input tensor containing probabilities, must be 1 or 2 dims.
-        num_samples (int) - number of samples to draw.
-        replacement (bool, optional) - whether to draw with replacement or not, default True.
-        seed (int, optional) - used as entropy source for Random number engines generating pseudo-random numbers.
+        inputs (Tensor): the input tensor containing probabilities, must be 1 or 2 dims. With float32 data type.
+        num_sample (int): number of samples to draw.
+        replacement (bool, optional): whether to draw with replacement or not, default True.
+        seed (int, optional): used as entropy source for Random number engines generating pseudo-random numbers.
           Must be non-negative. Default: 0.
 
     Outputs:
         Tensor. have the same rows with input, each row has num_samples sampled indices.
+        The dtype is float32.
 
     Examples:
         >>> input = Tensor([0, 9, 4, 0], mstype.float32)