diff --git a/tools/building.py b/tools/building.py
index d141797de42..26e13b3f84a 100644
--- a/tools/building.py
+++ b/tools/building.py
@@ -579,8 +579,8 @@ def DefineGroup(name, src, depend, **parameters):
     group['name'] = name
     group['path'] = group_path
     if type(src) == type([]):
-        # remove duplicate elements from list
-        src = list(set(src))
+        # remove duplicate elements from list while preserving order
+        src = list(dict.fromkeys(src))
         group['src'] = File(src)
     else:
         group['src'] = src
diff --git a/tools/targets/iar.py b/tools/targets/iar.py
index 39b28728e75..ee53ad2e001 100644
--- a/tools/targets/iar.py
+++ b/tools/targets/iar.py
@@ -131,10 +131,11 @@ def searchLib(group):
                     print('not found LIB: ' + item)
 
     # make relative path
-    paths = set()
+    paths = {}
     for path in CPPPATH:
         inc = _make_path_relative(project_path, os.path.normpath(path))
-        paths.add(inc) #.replace('\\', '/')
+        paths[inc] = None  # 使用 dict 去重并保持插入顺序
+    paths = list(paths.keys())
 
     # setting options
     options = tree.findall('configuration/settings/data/option')