diff --git a/mmcv/ops/points_in_polygons.py b/mmcv/ops/points_in_polygons.py
index 25b641d961..8d3bc8dd48 100644
--- a/mmcv/ops/points_in_polygons.py
+++ b/mmcv/ops/points_in_polygons.py
@@ -19,9 +19,8 @@ def points_in_polygons(points: Tensor, polygons: Tensor) -> Tensor:
         polygons (torch.Tensor): It has shape (M, 8), indicating
             (x1, y1, x2, y2, x3, y3, x4, y4). M means the number of
             ground truth polygons.
-        constraints: The absolute value of input range from e-10 to
-            e10 on NPU.
-
+        constraints: The number of significant digits for the input-arguments
+            are between -10 and 10 when running on Ascend device.
 
     Returns:
         torch.Tensor: Return the result with the shape of (B, M),