Abstract: This paper proposed an algorithm of automatic detection of fabric waterproof performance using image process and computer technology according to the properties of wet fabric and related standards.First,the image of the wet fabric was analyzed,and then,Canny operator and Otsu algorithm were used in detection of the fabric edge,its self-adaptiveness in the automatic detection of fabric waterproof performance was realized and its processing rate and choice of parameters were improved.Furthermore,morphological arithmetic process was used to get the closed edge of the wet fabric.