diff --git a/python/taichi/lang/_ndarray.py b/python/taichi/lang/_ndarray.py
index 30514bac43393..7c0298ac37935 100644
--- a/python/taichi/lang/_ndarray.py
+++ b/python/taichi/lang/_ndarray.py
@@ -4,7 +4,7 @@
 from taichi.lang.enums import Layout
 from taichi.lang.util import cook_dtype, python_scope, to_numpy_type
 from taichi.types import primitive_types
-from taichi.types.ndarray_type import SpecializeNdarrayType
+from taichi.types.ndarray_type import NdarrayTypeMetadata
 
 
 class Ndarray:
@@ -23,8 +23,7 @@ def __init__(self):
         self.arr = None
 
     def get_type(self):
-        return SpecializeNdarrayType(self.element_type, self.shape,
-                                     self.layout)
+        return NdarrayTypeMetadata(self.element_type, self.shape, self.layout)
 
     @property
     def element_shape(self):
diff --git a/python/taichi/lang/kernel_impl.py b/python/taichi/lang/kernel_impl.py
index e5365981c7932..fab88a564e267 100644
--- a/python/taichi/lang/kernel_impl.py
+++ b/python/taichi/lang/kernel_impl.py
@@ -337,13 +337,13 @@ def extract_arg(arg, anno):
             return arg
         if isinstance(anno, ndarray_type.NdarrayType):
             if isinstance(arg, taichi.lang._ndarray.ScalarNdarray):
-                anno.match(arg.get_type())
+                anno.check_matched(arg.get_type())
                 return arg.dtype, len(arg.shape), (), Layout.AOS
             if isinstance(arg, taichi.lang.matrix.VectorNdarray):
-                anno.match(arg.get_type())
+                anno.check_matched(arg.get_type())
                 return arg.dtype, len(arg.shape) + 1, (arg.n, ), arg.layout
             if isinstance(arg, taichi.lang.matrix.MatrixNdarray):
-                anno.match(arg.get_type())
+                anno.check_matched(arg.get_type())
                 return arg.dtype, len(arg.shape) + 2, (arg.n,
                                                        arg.m), arg.layout
             # external arrays
diff --git a/python/taichi/types/ndarray_type.py b/python/taichi/types/ndarray_type.py
index 61be06f25213c..58ce958f09cfe 100644
--- a/python/taichi/types/ndarray_type.py
+++ b/python/taichi/types/ndarray_type.py
@@ -1,7 +1,7 @@
 from taichi.types.primitive_types import f32
 
 
-class SpecializeNdarrayType:
+class NdarrayTypeMetadata:
     def __init__(self, element_type, shape=None, layout=None):
         self.element_type = element_type
         self.shape = shape
@@ -43,7 +43,7 @@ def __init__(self,
         self.field_dim = field_dim
         self.layout = layout
 
-    def match(self, ndarray_type: SpecializeNdarrayType):
+    def check_matched(self, ndarray_type: NdarrayTypeMetadata):
         if self.element_dim is not None and self.element_dim != len(
                 ndarray_type.element_type.shape):
             raise ValueError(