Abstract: This paper aims at the fast computation of the electromagnetic scattering from the large-scale sea surface by an approximate ray tracing(RT) method which is based on the two scale model(TSM-RT). Compared with the traditional RT method, TSM-RT method can decrease the number of intersections between the rays and facets, and keep a good accuracy. Therefore the computational efficiency is greatly improved. In addition, the parallelized accelerated TSM-RT method based on the graphics processing unit(GPU) is utilized in order to further improve the efficiency. According to the computational results, it demonstrates that the computational time of the GPU-based TSM-RT method is greatly decreased compared with the CPU-based TSM-RT method, therefore a good speedup ratio is achieved.