Abstract: In order to extract image edge information and eliminate noise，according to enlightenment of three indexes to evaluate the merit and inferior of edge detection by Canny and thinking of multiple structuring elements，two improvements are made to the general mathematic morphology edge detection： first，the image is filtered using compound mathematic morphology filter；second，the mathematic morphology edge detection operator with multiple structuring elements and noise elimination is constructed using multiple structuring elements thinking.The steps using this improved mathematic morphology edge detection algorithm are summarized.The experimental result indicates that this method can retain more edge information and resolve the conflict between Signal-to-Noise and single edge response to some extent.Finally，this method is used in the leakage test and a new leakage test method is obtained.