Abstract This paper presents a pulse electrical stress and measurement system of GaN high-electron-mobility transistors based on FPGA to apply the electrical stress accurately in the form of square wave pulses and switch to the measuring state in time. The design processes for the FPGA program, software system, and hardware circuit are discussed. The system uses a bipolar isolated gate driver to apply pulses of electrical stress to the gate of GaN HEMTs. The mode switch circuit is used to switch from “stress mode” to “measuring mode” to realize the measuring of electrical parameters of the device under test after stress. The system can achieve electrical pulse stress and assist in analyzing the degradation mechanism of GaN HEMTs.