The stress image method and the perfect matching layer method were used to deal with the boundary problem of shallow water ship seismic wave field simulation. The algorithm fully considers the shallow water environment and the excitation mechanism of the seismic wave. Based on the first-order velocity-stress equation, staggered grid finite difference method was taken to discretize the equations. The stress mirror method was applied to deal with free surface of seawater and air. The split boundary perfectly matched layer method was applied to deal with the boundary of the computing area. The parallel and inclined seafloor seismic wave fields were computed. The results before and after were compared, which shows that if the boundary is not treated, serious reflection would cover up the original wave field characteristics, but after the treatment, each case of wave field wave line and wave propagation rules are quite clear. So this method completely conforms to the shallow water ship seismic wave field numerical simulation requirements.