In this paper, an image mosaic algorithm based on feature points is proposed by making a study of the image mosaic methods and the characteristics of pathological image. Points of interest (POI) are firstly extracted by Moravec operator in this method, and the corresponding feature matches of the original images are achieved by correlation coefficient. The parameters of affine transformation are calculated by the matching feature points, and weighted average method is used to fuse images. The experimental results show that, as for the pathological image with translation and rotation, the algorithm can extract the matching feature points accurately and realize the image seamless mosaic.