Abstract:Phase-shift method is applicable to the accurate migration of steep geological structure in layered medium. However, this method has not found its wide application because of big computation and poor lateral velocity variation ability. To speed up the computation, seismic data are processed in partitioned way, then the processed seismic data are stored in disk in the same way. If the data processing is performed by vector computer, the vector Fourier transform program is preferred;and fast Fourier transform may be chosen when the data processing is done by scalar computer. Tine-consuming operatens relating to sine, cosine and evolution are finfished by consulting mathematical tables. The trial computation proves the method feasible.