Abstract: In order to investigate the dynamic behavior and liquefaction process of soil in elasto-plastic saturated sandy seabed induced by random waves according to realistic ocean environment, an elasto-plastic method of dynamic analysis is put forward by integrating Biot's dynamic consolidation theory with an elasto-plastic constitutive model for sand liquefaction and the associated numerical algorithm at zero effective confining stress state proposed by our research group. The proposed elasto-plastic method is capable of reproducing wave-induced transient change of excess pore pressure and soil liquefaction in saturated sandy seabed, of which the random wave is formed based on JONSWAP spectrum. The numerical calculation illustrates a basic tendency that under random waves the excess pore pressure fluctuates transiently, and meanwhile it accumulates or dissipates averagely. It is always shown that liquefaction occurs intermittently at intervals in time domain and that the region of liquefied soil propagates continuously in space domain.