diff --git a/docs/path.rst b/docs/path.rst
index fbcd8c9..b0ca341 100644
--- a/docs/path.rst
+++ b/docs/path.rst
@@ -16,8 +16,8 @@ Path
     Note that if ``path1`` is same as ``path2``, it's also regarded as
     the super path os ``path2``.
 
-    For instance "/opt" is the super path of "/opt/test",
-    While "/opt/t" is the super path of "/opt/test"
+    For instance "/", "/opt" and "/opt/test" are all the super paths of "/opt/test",
+    while "/opt/t" is the super path of "/opt/test".
 
     >>> from pydu.path import is_super_path
     >>> is_super_path('/aa/bb/cc', '/aa/bb/cc')
diff --git a/pydu/path.py b/pydu/path.py
index 16197c8..ceecc5c 100644
--- a/pydu/path.py
+++ b/pydu/path.py
@@ -18,8 +18,8 @@ def is_super_path(path1, path2):
     Whether `path1` is the super path of `path2`.
     Note that if `path1` is same as `path2`, it's also regarded as
     the super path os `path2`.
-    For instance "/opt" is the super path of "/opt/test",
-    While "/opt/t" is the super path of "/opt/test"
+    For instance "/", "/opt" and "/opt/test" are all the super paths of "/opt/test",
+    while "/opt/t" is the super path of "/opt/test".
     """
     path1 = os.path.normpath(path1)
     current_path2 = os.path.normpath(path2)