A shallow water flow model is parallelized with OpenMP and OpenACC to improve the computational efficiency.The Fujiangsha reach is used to validate the validity of the present model.Results of the numerical simulation indicate that the calculated results are in good agreement with the measured ones and there’s no obvious differences compared with the results of sequential program.The two modes of parallel processing can reduce largely the calculating time without losing accuracy.Moreover,the speed-up ratio of GPU parallel program reaches more than 6.7 times.