Abstract:H.264 video coding standard has become one of the mainstream standards because of its good compression ratio. In order to deal with the increasing complexity and computation in H.264 decoding, it is proposed in this paper that the parallel decoding optimization based on GPU which has the characteristics suitable for general parallel computing. Using GPU to decode intra prediction and filter modules, CPU controls GPU and decodes the remaining part. Based on the analysis of intra prediction decoding, a parallel intra prediction algorithm is also proposed, the experimental results of which show that the intra prediction decoding efficiency is increased by 20%. Through the study of the filter module, a parallel filtering algorithm and parallel filtering execution algorithm are proposed. It is proved by experiments the processing speed of the filter is increased by 30%, and the maximum ΔPSNR is 0.10 compared with the original image, and the ΔSSIM is 0.01. Finally, it is proved by experiments that using GPU to process the key modules of video decoding can greatly improve the processing efficiency.