In order to solve the problem of catalogue power supply in Mars exploration missions， the planning of taking liquid metal Rankine cycle as the thermal power conversion module of Mars catalogue base is developed. The Simulink modular modeling method is used to program the liquid metal Rankine cycle model. According to the coupling standard of each component of the space Rankine cycle， the simulation models for the system components and overall control are established. The fluctuation of the cycle output power under variable operating conditions is studied. The results show that the final output power of the Rankine cycle dynamic thermoelectric conversion simulation model can reach more than 1 MW under various working conditions， and the thermoelectric conversion efficiency can reach 27.3% under the rated working conditions， which fully meets the thermal power requirements of the system under the background of Mars detection. The Simulink modular modeling method can provide guidance for space nuclear power thermoelectric conversion simulation technology， and the relevant research results can provide valuable reference for China's Mars exploration plan in the future.