Abstract: In this paper, a new generation of scanning election microscope (SEM) and an energy spectrometer (ES) with the function of image analysis are combined used to analyse sandstone and cast sandstone. As SEM has the features of large field depth, strong relief perception and high resolution, the analysis of sandstone can use the secondary electron imagery and the back scatter imagery two methods respectively. By these methods, not only the intergranular pores, intergranular cement, throat connection, and coordination number of sandstone can be obtained, but also porosity factors can be calculated rapidly and quantitatively by means of image analytical software. The various information obtained combined with other data makes it possible to evaluate the reservoirs of specific areas.