diff --git a/tools/train.py b/tools/train.py
index 16ee091a..8e86c310 100644
--- a/tools/train.py
+++ b/tools/train.py
@@ -79,7 +79,7 @@ def build_opt_lr(model, current_epoch=0):
             m.eval()
     if current_epoch >= cfg.BACKBONE.TRAIN_EPOCH:
         for layer in cfg.BACKBONE.TRAIN_LAYERS:
-            for param in getattr(model.backbone, layer).parameters():
+            for param in getattr(model.backbone, layer)().parameters():
                 param.requires_grad = True
             for m in getattr(model.backbone, layer).modules():
                 if isinstance(m, nn.BatchNorm2d):