Abstract: A material performance test facility simulating the temperature and environment was built by Institute of Nuclear and New Energy Technology (INET) of Tsinghua University, by which kinds of tests at high temperatures of 1600 ℃ and below in carbon reducing environment could be conducted. Through rational simplification of the facility, the 2D mathematical model of the facility was introduced, which could simulate the dynamic heat transfer characterization including radiation and conduction at high temperature and under vacuum conduction. The simulating result is coincident with the measured temperature tendency and lots of dynamic heat transfer phenomenon observed in experiments could be explained. Furthermore, some key parameters which are difficult to be measured directly can be evaluated by the model, such as the radial temperature distribution of material test zone, the maximum temperature of the heater with different heating powers, which could give some instructive suggestions to further experiments.