Because of the inherent conflict between visual area and resolution in rock microscope structure, during the study of the RCTS (Rock Core Thin Section) microstructure, we cannot focus on the multi-scale structure characteristics of the particles, pores and throats, and it is fail to satisfy the demands of a more comprehensive study. In order to solve this problem, a microscopic image stitching method in RCTS is proposed by applying SIFT (Scale Invariant Feature Transform) detection algorithm. This method can successfully solve the conflict between the visual area and resolution, overcoming the problem of inclining and deformation in images acquisition under the microscope and finally, achieving the seamless stitching of RCTS microscopic image for big visual area. The experimental results show that this method can improve the accuracy of rock analysis in microstructure and has important practical and theoretical significance for the development of tight sandstone reservoir.