In this paper, we firstly study the two modules with highest computational complexity in AVS-M (Audio Video Coding Standard Working Group of ChinaMobile) decoder: motion compensation (MC) and deblocking filter (DF). Based on the detailed analysis of the concepts and principles of MC and DF, we present a new optimized AVS-M (OAVS-M). The experimental results show that both the value of PSNR and bitrate are improved. Then the structures of luma, chroma interpolation and DF have been designed to complete the functional and verification test.