Abstract: The working process of the space solar-dynamic power system is a dynamic process and the periodical change of eclipse and illumination period will influence system peformance. In order to study the dynamic characteristics of the system, a dynamic model was proposed by using the lumping method and dynamic simulation of the space solar-dynamic power system with electrical output power of 10 kW was performed. The simulation results indicated that the variations of temperature of phase change material and electrical output power with time were very small when the phase change materials were in the state of two phases, but the variations became bigger when the phase-change materials were in the state of single phase. In order to obtain a steady electrical output power, phase change material must be in the state of two phase by choosing a proper concentrator area.