Abstract: Image segmentation is one of basic research issues of image processing and computer vision.This paper makes some improvement to the Pal and King fuzzy edge-detection algorithm.A scheme for thresholding using genetic algorithms and Ostu is presented，according to optimal threshold a new line membership function is given，extending to more threshold.Then fuzzy enhancement is processing，at last rather fine image edge is gained.The experiment results show that this algorithm is not only higher segmentation quality but also higher computational speed，so it proves the algorithm is right and efficient.