In this paper, a real-time entropy decoder for HD video is designed, the whole decoding process is controlled under a finite state machine and the codeword is divided into three parts such as SPS/PPS/SliceHeader, CAVLC and EXP-Golomb. Due to variable length code, the five syntax elements of CAVLC will be parsed step by step. In the proposed implementation, a look-up table algorithm based on pos (the number of zero) is exploited and may be divided into sub-table according to priority in the same pos. The synthesis results show that the architecture can satisfy the requirement for a 1920??1080p@30fps high definition decoding.