Abstract: Most of existing channel simulation models need plenty of sinusoids and long simulation time，an improved sum-of-sinusoids（SOS）channel simulator based on random walk（RW）is proposed. Meanwhile，the theoretical expressions for the output channel fading envelope distributions and spatial-temporal correlation coefficients are derived in detail. The simulation results with 3GPP spatial channel model（SCM）propositional parameters show that the fading envelope distributions and spatial-temporal correlation properties of sub-channels agree well with the theoretical value，which are superior to the traditional model based on exact Doppler spread.Our improved channel simulator can be applied to real- time simulation for massive multiple- input multiple- output（MIMO）channels and multi-node network channels.