diff --git a/mmseg/models/decode_heads/sep_fcn_head.py b/mmseg/models/decode_heads/sep_fcn_head.py
index 21d108aba..c34eeef1f 100644
--- a/mmseg/models/decode_heads/sep_fcn_head.py
+++ b/mmseg/models/decode_heads/sep_fcn_head.py
@@ -30,8 +30,8 @@ class DepthwiseSeparableFCNHead(FCNHead):
         self.convs[0] = DepthwiseSeparableConvModule(
             self.in_channels,
             self.channels,
-            kernel_size=3,
-            padding=1,
+            kernel_size=self.kernel_size,
+            padding=self.kernel_size//2,
             norm_cfg=self.norm_cfg)
         for i in range(1, self.num_convs):
             self.convs[i] = DepthwiseSeparableConvModule(