Abstract: The traditional Canny edge detection operator requires human intervention,does not have the adaptive ability in the variance of Gaussian filtering and the lag threshold.The variance affects the edge preserving and de-noises ability effect.Morphological smoothing replaces Gaussian filtering,can not only maintain the edge information but also reduce noise impact.The lag threshold affects degree of the fake edges phenomenon and continuity of the real edges,Otsu method can specify the threshold adaptively,the edge detected is more continuous,and can decrease the false edges.With the experimental results,it has a certain degree of improvement on traditional Canny operator.