diff --git a/mmdet/models/necks/fpn.py b/mmdet/models/necks/fpn.py
index 9f601386549..f57b8effe65 100644
--- a/mmdet/models/necks/fpn.py
+++ b/mmdet/models/necks/fpn.py
@@ -15,8 +15,8 @@ class FPN(BaseModule):
     Detection <https://arxiv.org/abs/1612.03144>`_.
 
     Args:
-        in_channels (List[int]): Number of input channels per scale.
-        out_channels (int): Number of output channels (used at each scale)
+        in_channels (list[int]): Number of input channels per scale.
+        out_channels (int): Number of output channels (used at each scale).
         num_outs (int): Number of output scales.
         start_level (int): Index of the start input backbone level used to
             build the feature pyramid. Default: 0.
@@ -29,7 +29,7 @@ class FPN(BaseModule):
             Only the following options are allowed
 
             - 'on_input': Last feat map of neck inputs (i.e. backbone feature).
-            - 'on_lateral':  Last feature map after lateral convs.
+            - 'on_lateral': Last feature map after lateral convs.
             - 'on_output': The last output feature map after fpn convs.
         relu_before_extra_convs (bool): Whether to apply relu before the extra
             conv. Default: False.
@@ -37,10 +37,10 @@ class FPN(BaseModule):
             Default: False.
         conv_cfg (dict): Config dict for convolution layer. Default: None.
         norm_cfg (dict): Config dict for normalization layer. Default: None.
-        act_cfg (str): Config dict for activation layer in ConvModule.
+        act_cfg (dict): Config dict for activation layer in ConvModule.
             Default: None.
         upsample_cfg (dict): Config dict for interpolate layer.
-            Default: `dict(mode='nearest')`
+            Default: dict(mode='nearest').
         init_cfg (dict or list[dict], optional): Initialization config dict.
 
     Example: