Abstract: The energy system balance analysis is generally performed by table-calculation, which is not efficient and intuitive. This paper proposes a universal energy balance analysis method, which is visualized and easy to program, to replace the table-calculation method. The embedded MATLAB functions are used to program and implement the main function modules of the energy balance analysis. Based on the background of Mars rover EPS(electrical power system), the simulation system is built in MATLAB/SIMULINK and specific simulations are performed. The output figures and curves clearly show the dynamic trends of the energy utilization, which can help to decide and optimize the EPS design.