Abstract: The combined Block Digonalization precoding and Geometric Mean Decomposition (BD-GMD) scheme is developed to eliminate the multi-user interference and improve the system performance of bit error rate (BER) in a multiuser multiple input multiple output (MU-MIMO) .For the resource allocation and scheduling of BD-GMD system, the equal power allocation and water-filling algorithm for the impact of the system is compared.According to the subspace characteristics, a multi-user scheduling scheme based on maximizing the system throughput with low computational complexity is proposed.At the meantime, the brute-force search algorithm and conventional greedy algorithm is analyzed and compared with the proposed algorithm.Simulation results show that the proposed algorithm based on the orthogonal projection can reduce the computational complexity while maintaining the system throughput.