The PWM inverter is widely used in power systems due to its simple structure and flexible control. However, its IGBT transient characteristics are susceptible to junction temperature, which causes the output voltage of the PWM inverter circuit to be affected and distorted by temperature. Aiming at the above problems, this paper firstly determines the relationship between IGBT transient characteristics and junction temperature. Then, the mathematical relationship between IGBT transient characteristics and PWM inverter circuit output voltage harmonic is derived by Bessel function. Finally, under the MATLAB/Simulink environment, the PWM inverter circuit model considering IGBT transient switching characteristics is built to simulated. Theoretical analysis and simulation results show that the IGBT switching delay time has a positive temperature coefficient relationship; in the case of IGBT switching delay, the PWM inverter circuit output voltage adds DC and harmonic components, the total harmonic content increases, and the total rate of voltage distortion is rising.