Abstract: Based on the device physics simulation, focusing on the influence of pulse interval on thermal damage process of PIN limiter, the peak temperature of combined pulses with different pulse interval from 1 to 20 ns is studied. Numerical simulation results show that the pulse interval in which the device temperature rises most has a positive relationship with intrinsic region thickness. The thermal breakdown mechanism is analyzed. It is the spike leakage of the second sub-pulse that makes the temperature rise speed up. And the high temperature of the P-type region also causes the electrothermal feedback which makes it easier to get higher temperature.