Abstract: Put forward a method based on improved sub-pixel edge detection of gray moment of two-dimensional images, first of all on the two-dimensional image fast edge positioning, determine the coordinates of the image edge points; building a moment of gray image edge detection mathematical model based on, through the calculation and adjustment on both sides of the edge of the gray value, angle and orientation of parameters, edge linear equations; finally the 2D image edge error correction and noise removal treatment, two-dimensional image sub-pixel edge detection. Experiments show that the proposed method can effectively realize the image sub pixel edge detection in strong noise environment, which is more accurate, simple and fast operation.