Abstract: Emission and absorption in energy bind can be traced by Monte Carlo method.A new method named equivalent reflection model was developed to avoid calculating the board surface energy equation.Energy distributing and other parameters on cold surface of space outer-heat simulator with infrared thermal club were simulated by the method,and the simulation results on straight and bend clubs were compared.The result shows that energy distribution changes little with the surface emissivity changed by replacing the internal and external surface of the board,and the cold surface energy distribution can not keep uniform by adding thermal clubs.Heat distribution of the bend club is better than that of the straight one.