Abstract: The solar chimney power plant（SCPP）system is taken as the research object. The simulation results of SCPP temperature and velocity by constant heat flux,discrete ordinate（DO）radiation model and surface to surface（S2S）radiation model were compared. The simulation results of the three models were compared with the experimental data,and a more suitable radiation model was selected for SCPP numerical simulation.The results show that the maximum fluid velocity of S2S radiation model is 0.13 m/s and 0.36 m/s higher than that of constant heat flux and DO radiation model,respectively. The maximum turbulent viscosity of the S2S radiation model along the inlet of the chimney is 16.87% and 8.44% higher than that of the constant heat flux and DO radiation model,respectively. The errors of the fluid temperature along the radius of the heat collecting shed are 3.09%,0.98% and 10.14%,respectively,for the constant heat flux,DO radiation model and S2S radiation model. DO radiation model is more suitable for SCPP numerical model.