The purpose of this paper is to develop a suitable method for the defect region segmentation of strip surface images. Firstly, the traditional segmentation methods based on edge detection and global thresholding are studied and compared. Then, according to the gray-scale characteristics of strip surface defect images, a new segmentation method is proposed based on gray-scale morphology and adaptive thresholding. Finally, experimental results show the effectiveness of the proposed segmentation method compared with the traditional ones. Therefore, the proposed segmentation method has some practical value.