SAR(Synthetic Aperture Radar) images of sea targets are of great significance to the military. In view of the high cost of obtaining the measured data of sea targets SAR images, this paper implements a sea target SAR image simulation method based on electromagnetic scattering calculations. This method uses the Phillips spectrum to generate the sea surface geometric model, and combines the target model and the sea surface model; then uses the SBR(Shooting and Bouncing Rays) to calculate the electromagnetic scattering of the sea surface target; finally, the SAR image of the sea surface target is simulated by the RCS(Radar Cross Section) obtained by the calculation. Through the analysis of the results of different sea states and different incident angles, it is shown that this method can complete the SAR image simulation of sea surface targets at different sea states and different angles, and the simulation effect is relatively realistic.