For the shortcoming of the traditional Canny algorithm,an improved Canny edge detection algorithm is proposed combining with the characteristics of laser active imaging.Based on Canny edge detection algorithm,the homomorphic filtering and lifting wavelet transform are adopted to replace the traditional Gaussian filter;a weight gradient method of 3×3 adjacent regions is used to replace difference method of 2×2 adjacent regions.Finally,Otsu algorithm and gradient histogram are used to get appropriate thresholds adaptively based on the features of the image.Experimental results show that the algorithm can improve the anti-interference ability and robustness of traditional Canny operator and keep the edge information,and it can detect the image edge of laser active imaging,so it has strong adaptability.