diff --git a/ppcls/arch/backbone/base/theseus_layer.py b/ppcls/arch/backbone/base/theseus_layer.py
index 4b1914816f331f797aeb563ab7488abe536145b2..12a7a2729dfc682a5a58d96207b7e8a0f3ab4002 100644
--- a/ppcls/arch/backbone/base/theseus_layer.py
+++ b/ppcls/arch/backbone/base/theseus_layer.py
@@ -66,53 +66,22 @@ class TheseusLayer(nn.Layer):
 
         handle_res_dict = {}
         for pattern in layer_name_pattern:
-            pattern_list = pattern.split(".")
+            # pattern_list = pattern.split(".")
 
             # find parent layer of sub-layer specified by pattern
-            sub_layer_parent = self
-            while len(pattern_list) > 1:
-                if '[' in pattern_list[0]:
-                    sub_layer_name = pattern_list[0].split('[')[0]
-                    sub_layer_index = pattern_list[0].split('[')[1].split(']')[
-                        0]
-                    sub_layer_parent = getattr(sub_layer_parent,
-                                               sub_layer_name)[sub_layer_index]
-                else:
-                    sub_layer_parent = getattr(sub_layer_parent,
-                                               pattern_list[0], None)
-                    if sub_layer_parent is None:
-                        break
-                if isinstance(sub_layer_parent, WrapLayer):
-                    sub_layer_parent = sub_layer_parent.sub_layer
-                pattern_list = pattern_list[1:]
-            if sub_layer_parent is None:
-                msg = f"Not found parent layer of sub-layer by name({pattern_list[0]}) specifed in pattern({pattern})."
-                logger.warning(msg)
+            sub_layer_parent, _, _ = parse_pattern_str(
+                pattern=pattern, idx=(0, -1), sub_layer_parent=self)
+
+            if not sub_layer_parent:
                 continue
 
             # find sub-layer specified by pattern
-            if '[' in pattern_list[0]:
-                sub_layer_name = pattern_list[0].split('[')[0]
-                sub_layer_index = pattern_list[0].split('[')[1].split(']')[0]
-            else:
-                sub_layer_name = pattern_list[0]
-                sub_layer_index = None
-
-            sub_layer = getattr(sub_layer_parent, sub_layer_name, None)
+            sub_layer, sub_layer_name, sub_layer_index = parse_pattern_str(
+                pattern=pattern, idx=-1, sub_layer_parent=sub_layer_parent)
 
             if not sub_layer:
-                msg = f"Not found sub-layer by name({pattern_list[0]}) specifed in pattern({pattern})."
-                logger.warning(msg)
                 continue
 
-            if sub_layer_index is not None:
-                if int(sub_layer_index) < 0 or int(sub_layer_index) >= len(
-                        sub_layer):
-                    msg = f"Not found sub-layer by index({sub_layer_index}) specifed in pattern({pattern})."
-                    logger.warning(msg)
-                    continue
-                sub_layer = sub_layer[sub_layer_index]
-
             new_sub_layer = handle_func(sub_layer, pattern)
 
             if sub_layer_index:
@@ -156,6 +125,7 @@ class TheseusLayer(nn.Layer):
         pattern_list = stop_layer_name.split(".")
         to_identity_list = []
 
+        # TODO(gaotingquan): replace code by self._parse_pattern_str()
         layer = self
         while len(pattern_list) > 0:
             layer_parent = layer
@@ -219,5 +189,67 @@ class WrapLayer(TheseusLayer):
 
 
 def wrap_theseus(sub_layer):
-    wrapped_layer = WrapLayer(sub_layer)
-    return wrapped_layer
+    return WrapLayer(sub_layer)
+
+
+def unwrap_theseus(sub_layer):
+    if isinstance(sub_layer, WrapLayer):
+        sub_layer = sub_layer.sub_layer
+    return sub_layer
+
+
+def slice_pattern(pattern, idx):
+    pattern_list = pattern.split(".")
+    if idx:
+        if isinstance(idx, tuple):
+            if len(idx) == 1:
+                return pattern_list[idx[0]]
+            elif len(idx) == 2:
+                return pattern_list[idx[0]:idx[1]]
+            else:
+                msg = f"Only support length of 'idx' is 1 or 2 when 'idx' is a tuple."
+                logger.warning(msg)
+                return None
+        elif isinstance(idx, int):
+            return [pattern_list[idx]]
+        else:
+            msg = f"Only support type of 'idx' is int or tuple."
+            logger.warning(msg)
+            return None
+
+    return pattern_list
+
+
+def parse_pattern_str(pattern, sub_layer_parent, idx=None):
+    pattern_list = slice_pattern(pattern, idx)
+    if not pattern_list:
+        return None, None, None
+
+    while len(pattern_list) > 0:
+        if '[' in pattern_list[0]:
+            sub_layer_name = pattern_list[0].split('[')[0]
+            sub_layer_index = pattern_list[0].split('[')[1].split(']')[0]
+        else:
+            sub_layer_name = pattern_list[0]
+            sub_layer_index = None
+
+        sub_layer_parent = getattr(sub_layer_parent, sub_layer_name, None)
+        sub_layer_parent = unwrap_theseus(sub_layer_parent)
+
+        if sub_layer_parent is None:
+            msg = f"Not found layer named({sub_layer_name}) specifed in pattern({pattern})."
+            logger.warning(msg)
+            return None, sub_layer_name, sub_layer_index
+
+        if sub_layer_index and sub_layer_parent:
+            if int(sub_layer_index) < 0 or int(sub_layer_index) >= len(
+                    sub_layer_parent):
+                msg = f"Not found layer by index({sub_layer_index}) specifed in pattern({pattern}). The lenght of sub_layer's parent layer is < '{len(sub_layer_parent)}' and > '0'."
+                logger.warning(msg)
+                return None, sub_layer_name, sub_layer_index
+            sub_layer_parent = sub_layer_parent[sub_layer_index]
+            sub_layer_parent = unwrap_theseus(sub_layer_parent)
+
+        pattern_list = pattern_list[1:]
+
+    return sub_layer_parent, sub_layer_name, sub_layer_index