A novel power clamp circuit was proposed, which aimed to solve the problems of large leakage current, false triggering, and low on-time in traditional circuits. This circuit used the current amplification of a bipolar transistor (BJT) to reduce the capacitance value, and the feedback function of a MOS tube and a series diode was used to adjust the trigger voltage. In this way, the performance of the clamp circuit could be improved. The simulation results showed that the circuit could quickly respond to ESD events, and could achieve a fast shutdown function, thereby quickly discharging current and avoiding damage to the internal circuit.