Abstract: Power System Analysis Software Package (PSASP)is a software commonly used in simulation of electricity power system, and Simulink is a visible power system simulation tool of Matlab.Both softwares have a strong power system analysis and calculation functions.In this paper, a four node system is used to simulated calculate by two softwares respectively, and the results are compared and analyzed.The experimental results show that Matlab is more suitable for the specific models or high precision simulation, but the operation of Matlab for power flow calculation is more complicated.PSASP is more suitable for the modeling and steady state calculation under the condition of less parameters or ideal conditions.