Abstract: In this paper,the principle of modeling of IGBT by using MATLAB simulation software is introduced in detail. IGBT model is built on an ideal switch block,which has been given in the MATLAB, and nonlinear resistor,which is in series with the ideal switch and has the same output characteristics with IGBT. The model is simulated in static and dynamic states,and the results obtained are in agreement with the data given by the date book. In addition,the struchture of the model has a powerful flexibility,and other kinds of IGBT or power switches can be simulated very well when their parameters are inputted into the model. The foundation of IGBT nmodel meets the needs for the simulation of the new circuit, and the model plays the important role in the developing new inverter resistance welding machine.