diff --git a/obpoplugin/idahelper.py b/obpoplugin/idahelper.py
index 36145b9..c5c36e7 100644
--- a/obpoplugin/idahelper.py
+++ b/obpoplugin/idahelper.py
@@ -18,6 +18,18 @@ def get_block_start(ea):
     return ea
 
 
+def set_block_color(ea, color):
+    func = get_func(ea)
+    if not func:
+        return
+    c = FlowChart(func)
+    for block in c:
+        if block.start_ea <= ea < block.end_ea:
+            ni = node_info_t()
+            ni.bg_color = color
+            set_node_info(func.start_ea, block.id, ni, NIF_BG_COLOR)
+
+
 def visit_instructions(bb: mblock_t):
     if not bb or not bb.head:
         return []
diff --git a/obpoplugin/manager.py b/obpoplugin/manager.py
index da4d4d5..77c2db4 100644
--- a/obpoplugin/manager.py
+++ b/obpoplugin/manager.py
@@ -3,7 +3,7 @@
 # CreateTime: 2022/3/22
 from ida_hexrays import mba_t
 from ida_idaapi import BADADDR
-from obpoplugin.idahelper import get_func_start, get_block_start
+from obpoplugin.idahelper import get_func_start, get_block_start, set_block_color
 
 
 # Mark Manager
@@ -15,17 +15,25 @@ def __init__(self):
     def mark(self, ea):
         s = self.func_marked(ea)
         s.add(get_block_start(ea))
+        set_block_color(ea, 0x00ff00)
 
     def unmark(self, ea):
         s = self.func_marked(ea)
         ea = get_block_start(ea)
-        if ea in s: s.remove(ea)
+        if ea in s:
+            set_block_color(ea, 0xffffff)
+            s.remove(ea)
 
     def unmark_func(self, ea):
         s = self.func_marked(ea)
+        for ea in s:
+            set_block_color(ea, 0xffffff)
         s.clear()
 
     def clear(self):
+        for s in self.marked.values():
+            for ea in s:
+                set_block_color(ea, 0xffffff)
         self.marked.clear()
 
     def func_marked(self, ea):