diff --git a/tools/building.py b/tools/building.py
index a90ad69c1d284abe5cea58fcb0d52ecc979ff003..6b752674b52b95076f7b43bcd708da6bc834b578 100644
--- a/tools/building.py
+++ b/tools/building.py
@@ -83,6 +83,11 @@ def PrepareBuilding(env, root_directory, has_libcpu=False, remove_components = [
                       action='store_true',
                       default=False,
                       help='copy header of rt-thread directory to local.')
+    AddOption('--cscope',
+                      dest='cscope',
+                      action='store_true',
+                      default=False,
+                      help='Build Cscope cross reference database. Requires cscope installed.')
 
     # add build library option
     AddOption('--buildlib', 
@@ -341,6 +346,10 @@ def EndBuilding(target, program = None):
     if GetOption('copy-header') and program != None:
         MakeCopyHeader(program)
 
+    if GetOption('cscope'):
+        from cscope import CscopeDatabase
+        CscopeDatabase(Projects)
+
 def SrcRemove(src, remove):
     if type(src[0]) == type('str'):
         for item in src:
diff --git a/tools/cscope.py b/tools/cscope.py
new file mode 100644
index 0000000000000000000000000000000000000000..18568b4c355028a46c67f864533535b78fedaf0a
--- /dev/null
+++ b/tools/cscope.py
@@ -0,0 +1,37 @@
+import os
+
+def _get_src(project):
+    li = []
+    for group in project:
+        for f in group['src']:
+            li.append(os.path.normpath(f.rfile().abspath))
+    return li
+
+def _get_header_dir(dirp):
+    li = []
+    for root, dirs, files in os.walk(dirp):
+        for d in dirs:
+            fpath = os.path.join(root, d)
+            li.extend(_get_header_dir(fpath))
+
+        for f in files:
+            if f[-2:] == '.h':
+                fpath = os.path.join(root, f)
+                li.append(os.path.normpath(fpath))
+    return li
+
+def _get_header(project):
+    li = []
+    for g in project:
+        for d in g.get('CPPPATH', []):
+            li.extend(_get_header_dir(d))
+    return li
+
+def CscopeDatabase(project):
+    files = set(_get_src(project) + _get_header(project))
+    with open('cscope.files', 'w') as db:
+        db.write('-k\n-q\n')
+        db.write('\n'.join(files))
+        db.flush() # let cscope see the full content
+        os.system('cscope -b')
+