In a single-cell system where the base station and multiple users are multi-antenna hybrid beamforming architectures and the channel is an ideal millimeter-wave channel， aiming at the problem of maximum total spectral efficiency， a low-complexity hybrid beamforming algorithm is proposed. The program uses a step-by-step approach. First， the analog beamforming matrix of the base station and the mobile station is solved respectively. Baseband channel is obtained based on the analog beamforming matrix. Then the block diagonal digital beamforming algorithm is used to get the digital beamforming matrix. Simulation results show that， compared with other schemes， this scheme also improves the overall spectrum efficiency of the system while reducing the complexity.