Abstract In this paper, a novel gate-series-diode structure for the Schottky-type p-GaN HEMTs is proposed, and the impact of the proposed structure on gate−source voltage oscillation is investigated when the device is turned on. The proposed structure is capable of effectively mitigating the gate−source voltage overshoot problem of GaN device, and has little effect on the switching characteristics. The gate voltage oscillations can be greatly stabilized at the steady-state turn-on voltage level when the turn-on voltage is 5 V. Compared with the conventional structure, the overshoots of the proposed structure reduce by 31.4%−71.4% and 40.6%−80.4% respectively under the two pulses, as drain−source voltage rises. The proposed structure is proved to be a potential method on improving gate reliability of the most GaN power devices.