Laser active imaging system can obtain intensity image, range image and velocity image, and it provides more useful information than other imaging systems. According to the features of laser active imaging, a new edge detection algorithm of laser active image based on wavelet transform and multi-scale morphology is presented. The wavelet multi-resolution analysis is used to differentiate the noise and the edge detail of the image, and then a non-linear algorithm is constructed to strengthen the wake parts of the image. The concept of the multi-scale morphology is introduced to obtain the edge of the processed image, bigger morphology operator eliminating noise and smaller morphology operator is used to pick up image detail, and the better edge of the processed image is obtained. The experimental results indicate that compared with classical edge detection operator, this method has better noise immunity and performance on edge detection of laser active imaging with large noise and blurry edge.