Abstract: In order to overcome the wireless mobile channel time-varying and multi-path fading effects on signal transmission, the technology of Hybrid Automatic Repeat Request(HARQ) in Worldwide Interoperability for Microwave Access (WiMAX) system can improve the reliability of data transmission, thereby ensuring the quality of service. The conventional HARQ algorithm without combining requires little mount of memory and has low complexity, but is poor in the bit error rate(BER) and throughput performance; The HARQ algorithm with combining decoding can improve the BER and throughput performance, but requires more mount of memory and increases the computing complexity. For the sake of conquering the two shortages above, this paper proposes a novel combining HARQ scheme named MLD-CSI based on majority logic decision principle and channel impulse response power, which integrates majority logical decision principle with optimality decision principle to combine the transmitted packets before decoding at the receiver. Computer simulations under the time-varying and multi-path fading environment show the performances of the proposed algorithm which align well with the analysis, by contrast with the MRC HARQ algorithm, the proposed algorithm requires less mount of memory and has lower complexity when reserving good performance. Therefore, the proposed algorithm is an efficient and feasible scheme for practical systems.