diff --git a/fastNLP/modules/__init__.py b/fastNLP/modules/__init__.py
index 769dc42a..d72d2022 100644
--- a/fastNLP/modules/__init__.py
+++ b/fastNLP/modules/__init__.py
@@ -36,6 +36,7 @@ __all__ = [
 
     "MaxPool",
     "MaxPoolWithMask",
+    "KMaxPool",
     "AvgPool",
     "AvgPoolWithMask",
 
diff --git a/fastNLP/modules/encoder/__init__.py b/fastNLP/modules/encoder/__init__.py
index 7fbc4b71..cbb42d7e 100644
--- a/fastNLP/modules/encoder/__init__.py
+++ b/fastNLP/modules/encoder/__init__.py
@@ -23,6 +23,7 @@ __all__ = [
 
     "MaxPool",
     "MaxPoolWithMask",
+    "KMaxPool",
     "AvgPool",
     "AvgPoolWithMask",
 
@@ -36,7 +37,7 @@ from .bert import BertModel
 from .char_encoder import ConvolutionCharEncoder, LSTMCharEncoder
 from .conv_maxpool import ConvMaxpool
 from .lstm import LSTM
-from .pooling import MaxPool, MaxPoolWithMask, AvgPool, AvgPoolWithMask
+from .pooling import MaxPool, MaxPoolWithMask, AvgPool, AvgPoolWithMask, KMaxPool
 from .star_transformer import StarTransformer
 from .transformer import TransformerEncoder
 from .variational_rnn import VarRNN, VarLSTM, VarGRU
diff --git a/fastNLP/modules/encoder/pooling.py b/fastNLP/modules/encoder/pooling.py
index 789b6d26..80ff419d 100644
--- a/fastNLP/modules/encoder/pooling.py
+++ b/fastNLP/modules/encoder/pooling.py
@@ -3,6 +3,7 @@
 __all__ = [
     "MaxPool",
     "MaxPoolWithMask",
+    "KMaxPool",
     "AvgPool",
     "AvgPoolWithMask"
 ]
@@ -27,7 +28,7 @@ class MaxPool(nn.Module):
         :param ceil_mode:
         """
         super(MaxPool, self).__init__()
-        assert (1 <= dimension) and (dimension <= 3)
+        assert dimension in [1, 2, 3], f'Now we only support 1d, 2d, or 3d Pooling'
         self.dimension = dimension
         self.stride = stride
         self.padding = padding
@@ -37,12 +38,12 @@ class MaxPool(nn.Module):
 
     def forward(self, x):
         if self.dimension == 1:
+            x = torch.transpose(x, 1, 2)  # [N,L,C] -> [N,C,L]
             pooling = nn.MaxPool1d(
                 stride=self.stride, padding=self.padding, dilation=self.dilation,
                 kernel_size=self.kernel_size if self.kernel_size is not None else x.size(-1),
                 return_indices=False, ceil_mode=self.ceil_mode
             )
-            x = torch.transpose(x, 1, 2)  # [N,L,C] -> [N,C,L]
         elif self.dimension == 2:
             pooling = nn.MaxPool2d(
                 stride=self.stride, padding=self.padding, dilation=self.dilation,
@@ -50,7 +51,7 @@ class MaxPool(nn.Module):
                 return_indices=False, ceil_mode=self.ceil_mode
             )
         else:
-            pooling = nn.MaxPool2d(
+            pooling = nn.MaxPool3d(
                 stride=self.stride, padding=self.padding, dilation=self.dilation,
                 kernel_size=self.kernel_size if self.kernel_size is not None else (x.size(-3), x.size(-2), x.size(-1)),
                 return_indices=False, ceil_mode=self.ceil_mode
diff --git a/test/modules/encoder/test_pooling.py b/test/modules/encoder/test_pooling.py
new file mode 100644
index 00000000..5adca4ff
--- /dev/null
+++ b/test/modules/encoder/test_pooling.py
@@ -0,0 +1,41 @@
+import unittest
+
+import torch
+
+from fastNLP.modules.encoder.pooling import MaxPool, MaxPoolWithMask, KMaxPool, AvgPool, AvgPoolWithMask
+
+
+class TestPooling(unittest.TestCase):
+    def test_MaxPool(self):
+        max_pool_1d = MaxPool(dimension=1)
+        x = torch.randn(5, 6, 7)
+        self.assertEqual(max_pool_1d(x).size(), (5, 7))
+
+        max_pool_2d = MaxPool(dimension=2)
+        self.assertEqual(max_pool_2d(x).size(), (5, 1))
+
+        max_pool_3d = MaxPool(dimension=3)
+        x = torch.randn(4, 5, 6, 7)
+        self.assertEqual(max_pool_3d(x).size(), (4, 1, 1))
+
+    def test_MaxPoolWithMask(self):
+        pool = MaxPoolWithMask()
+        x = torch.randn(5, 6, 7)
+        mask = (torch.randn(5, 6) > 0).long()
+        self.assertEqual(pool(x, mask).size(), (5, 7))
+
+    def test_KMaxPool(self):
+        k_pool = KMaxPool(k=3)
+        x = torch.randn(4, 5, 6)
+        self.assertEqual(k_pool(x).size(), (4, 15))
+
+    def test_AvgPool(self):
+        pool = AvgPool()
+        x = torch.randn(4, 5, 6)
+        self.assertEqual(pool(x).size(), (4, 5))
+
+    def test_AvgPoolWithMask(self):
+        pool = AvgPoolWithMask()
+        x = torch.randn(5, 6, 7)
+        mask = (torch.randn(5, 6) > 0).long()
+        self.assertEqual(pool(x, mask).size(), (5, 7))