Abstract: In order to improve the imaging effect of large faults and small faults in Weixi block, through the application of pre-stack reverse time migration technology for the test analysis and trial treatment of multiple rounds, the key problem which affects the RTM imaging effect of offshore complex structures has been found. Technical methods have been optimized such as unilateral gun observation aperture definition, widescreen RTM algorithm (optimization of Laplace algorithm for low frequency protection) and RTM illumination compensation. Corresponding RTM modules also have been developed. The results of the test application have formed a set of technical parameters about RTM technology for fine imaging in Weixi block. The effect of RTM imaging processing has been gradually improved in the research process. The large tomography and the fault point relocation are clearer and more accurate than the previous results and the depth before the stacking, the credibility of structural imaging is improved, the basement structure is continuously clear, especially in the effect of steep inclination formation and small tomography becomes better.