Due to independence of weather condition and sun illumination, Synthetic Aperture Radar (SAR) has been widely used in airborne remote sensing and satellite ocean observation fields. With the increase in swath and higher resolution requirements, SAR imaging algorithms require further study. However, as a research support, echo data has massive increase. So the high efficient echo simulation is required emergently. SAR echo simulation is optimized to accelerate, based on AVX/SSE of vector instruction set and OpenMP. Experiments demonstrate that in the case of using OpenMP and AVX / SSE combined, CPU simulation efficiency is improved by about 23 times, compared to the traditional one.