Abstract: In order to study remaining oil distribution features in the porous media of formation under the condition of different displacement, the author used special glass materials to make microscopic visualization model which was close to the natural core pore throat characteristics. During the making process, digital images of the natural core chip and the casting thin sections have been used as well as etching technology. The mode's maximum bearing pressure was 20 MPa and maximum bearing temperature was 100 ℃. The results showed that the model was well applied in the study of residual oil of CO₂ flooding experiment. Using special glass material has the advantage of light transmission, and the shooting effect is clear, which is helpful for observation and summary. In this paper, the image resolution method to describe the residual oil by software was used. The research results have important theoretical and practical guiding significance for the study of microcosmic residual oil, and deepen the understanding of mechanism.