diff --git a/tools/building.py b/tools/building.py
index 6e26a19e5f4..d141797de42 100644
--- a/tools/building.py
+++ b/tools/building.py
@@ -825,7 +825,7 @@ def GenTargetProject(program = None):
     if GetOption('target') == 'iar':
         from targets.iar import IARProject, IARVersion
         print("IAR Version: " + IARVersion())
-        IARProject(GetOption('project-name') + '.ewp', Projects)
+        IARProject(Env, GetOption('project-name') + '.ewp', Projects)
         print("IAR project has generated successfully!")
 
     if GetOption('target') == 'vs':
@@ -934,7 +934,7 @@ def EndBuilding(target, program = None):
             if not isinstance(project_path, str) or len(project_path) == 0:
                 project_path = os.path.join(BSP_ROOT, 'rt-studio-project')
             MkDist(program, BSP_ROOT, Rtt_Root, Env, project_name, project_path)
-            child = subprocess.Popen('scons --target=eclipse --project-name="{}"'.format(project_name), 
+            child = subprocess.Popen('scons --target=eclipse --project-name="{}"'.format(project_name),
                                    cwd=project_path, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
             stdout, stderr = child.communicate()
             need_exit = True
diff --git a/tools/targets/iar.py b/tools/targets/iar.py
index 99223b24bab..39b28728e75 100644
--- a/tools/targets/iar.py
+++ b/tools/targets/iar.py
@@ -77,7 +77,7 @@ def IARWorkspace(target):
     out.write(xml)
     out.close()
 
-def IARProject(target, script):
+def IARProject(env, target, script):
     project_path = os.path.dirname(os.path.abspath(target))
 
     tree = etree.parse('template.ewp')
@@ -86,7 +86,7 @@ def IARProject(target, script):
     out = open(target, 'w')
 
     CPPPATH = []
-    CPPDEFINES = []
+    CPPDEFINES = env.get('CPPDEFINES', [])
     LOCAL_CPPDEFINES = []
     LINKFLAGS = ''
     CFLAGS = ''
@@ -112,9 +112,6 @@ def searchLib(group):
         if 'CPPPATH' in group and group['CPPPATH']:
             CPPPATH += group['CPPPATH']
 
-        # get each group's definitions
-        if 'CPPDEFINES' in group and group['CPPDEFINES']:
-            CPPDEFINES += group['CPPDEFINES']
 
         if 'LOCAL_CPPDEFINES' in group and group['LOCAL_CPPDEFINES']:
             LOCAL_CPPDEFINES += group['LOCAL_CPPDEFINES']