Abstract: In view of the important inffluence of the the themal behavior of the space computer on the control and lifetime of the spacecraft, the software SolidEdge is used, combined with FloTHERM to make thermodynamic analyses of the space computer. The simplifications ofthe model ofme space computer are made by SolidEdge and FloTHERM to guarantee me accuracy and the efficiency of the calculation. Based on aIl analysis of the heat source of the PCB, the boundary parameters are detemined and the themodynamic equation is solved. According to the power consumption of the PCBs and me PC box, the themodynamic model of every pans is built. The temperature distributions of every part and its key elements are obtained. The results provide some guidance for selecting design parameters and predicting failure of the space computer.