A novel method is depicted in this paper to handle the probably existed false corners from the feature extraction on calibration image using Harris operator. It performs x and y directional sub-pixel scans in the neighborhood of false corners respectively, then line fitting or curve fitting method based on orthogonal distance is employed to compute the intersection of two edge lines for the purpose of replacing the location of false corner. A lot of experiments on the images of chessboard for machine calibration show that the method is of robustness, and achieve two expectant objectives: 1) amend false corners in result; 2) get the sub-pixel level corners of high accuracy.