Electromagnetic calculation and SAR echo simulation algorithm play an important role in radar system design, radar algorithm verification, and automatic target recognition algorithms research. To solve the problem of traditional electromagnetic calculation and SAR echo simulation algorithm being too time-consuming, an acceleration method for the entire process based on GPU is proposed. Firstly, the three core computing parts of the traditional algorithm-ray tracing, electromagnetic calculation,and SAR echo simulation are divided into multiple threads. Then, by using the GPU general computing platform, all thread units are processed in parallel to accelerate the simulation speed. Finally, the experimental results show that the acceleration ratio of this method is about 450 compared with single-core CPU and about 50 compared to a 10-core CPU. This method achieves a good acceleration effect on the premise that the generated data is consistent with the traditional algorithm.