Abstract: Aiming at the power requirements of the deep-space exploration, a set of the thermo-photovoltaic system with heat pipe is designed in this article. The separate gravity heat pipe is employed to realize the thermal control requirement, and the thermo-electric conversion capability of the TPV system is confirmed. The effect of the thermal power, amount of the working fluid on the startup performance, wall temperature is investigated. Also the influence of the temperature of the emitter and the cell on the system electrical output performance is analyzed. The results indicate that the heat pipe can control the cell temperature below 25℃.While the emitter temperature reaches 1 173℃, the thermal-electric conversion efficiency reaches 12.1%.