The rigorous coupled-wave analysis of two-dimensional gratings is revived. Parallel computing method is introduced in the codes based on RCWA. Hybrid computation using GPU with CPU is used to improve the efficiency of the RCWA simulation program, There are combination of highly parallel computing ability of GPU, and the fast serial computing ability of CPU. a typical calculation for 2-D grating shows that the computing speed can be accelerated by using the parallel computing method. the test used two CPU based math libraries-LAPACK, MKL, and the GPU code we have built. in this test, both single process and multi process are used in the same platform.