Abstract: The widely distributed faults in the Weixinan Sag are the main cause to the complexity of sand body distribution and connectivity. Conventional seismic data, due to its unclear images, is difficult to sand body recognition. Faced with these problems, in order to improve the image quality of seismic data, we, for the first time, introduced the reverse-time migration technology in the complex fault block of the Weixinan oil field in order to solve the problem of seismic wave propagation path. During the process, after test of methods and parameters, an accurate velocity model is setting up, that makes the reverse-time migration technology applicable to the Weixinan oilfields. Results show that the technology could effectively improve the quality of seismic data, and recognize the small fault features and characteristics of sand bodies. During the development of the oilfield, it is confirmed that the results are reliable, and could provide a powerful technical means in similar cases.