Abstract:Through systematically studying on the method separating P-wave from S-wave by second-order elastic wave equation and first-order staggered grid algorithm,the paper presented the formula representation simulating P-and S-waves separation in first-order staggered grid.The P-and S-waves are naturally separated but do not be coupled together in a simulating process of the method,producing full P-wave and full S-wave simulated records.The results of numeric simulation showed the correctness of the method.There is important practical meaning for knowing propagation rule of elastic wave and guiding numeric simulation of reservoir by study of full P-wave and full S-wave simulation.