diff --git a/ppcls/optimizer/__init__.py b/ppcls/optimizer/__init__.py
index b7b4d42105ea8f71d41f12f4a93423ea65707e2f..a440eac463e2a5ebd74cf676b2487973baea9546 100644
--- a/ppcls/optimizer/__init__.py
+++ b/ppcls/optimizer/__init__.py
@@ -58,6 +58,12 @@ def build_optimizer(config, epochs, step_each_epoch, model_list=None):
         }]
     optim_list = []
     lr_list = []
+    """NOTE:
+    Currently only support optim objets below.
+    1. single optimizer config.
+    2. next level uner Arch, such as Arch.backbone, Arch.neck, Arch.head.
+    3. loss which has parameters, such as CenterLoss.
+    """
     for optim_item in optim_config:
         # optim_cfg = {optim_name: {scope: xxx, **optim_cfg}}
         # step1 build lr
@@ -91,11 +97,19 @@ def build_optimizer(config, epochs, step_each_epoch, model_list=None):
             if len(model_list[i].parameters()) == 0:
                 continue
             if optim_scope == "all":
+                # optimizer for all
                 optim_model.append(model_list[i])
             else:
-                for m in model_list[i].sublayers(True):
-                    if m.__class__.__name__ == optim_scope:
-                        optim_model.append(model_list[i])
+                if optim_scope.endswith("Loss"):
+                    # optimizer for loss
+                    for m in model_list[i].sublayers(True):
+                        if m.__class_name == optim_scope:
+                            optim_model.append(m)
+                else:
+                    # opmizer for module in model, such as backbone, neck, head...
+                    if hasattr(model_list[i], optim_scope):
+                        optim_model.append(getattr(model_list[i], optim_scope))
+
         assert len(optim_model) == 1, \
             "Invalid optim model for optim scope({}), number of optim_model={}".format(optim_scope, len(optim_model))
         optim = getattr(optimizer, optim_name)(