The third-generation power semiconductor device-gallium nitride high electron mobility transistor (GaN HEMT) has been widely used in the fields of power electronics and communication electronics due to its excellent voltage and temperature tolerance. GaN HEMT devices usually work under harsh external conditions such as high temperature and high power. In order to avoid the sudden failure of GaN HEMT devices from affecting the normal operation of power electronic equipment, it is of great significance to carry out active real-time state detection. By designing and conducting repetitive experiments under different temperature and drain-source voltage conditions, the energy of the device stress wave is extracted and analyzed to explore the effects of temperature and drain-source voltage on the GaN HEMT. Aiming at the problem that the device stress wave acquisition process is susceptible to noise interference, a stress wave denoising algorithm based on variational mode decomposition (VMD) of goose optimization algorithm is proposed. The experimental results show that the proposed GOOSE-VMD signal processing method can achieve good noise reduction while preserving the characteristics of stress wave signals to the greatest extent possible; there is a good positive correlation between the device stress wave energy and drainsource voltage; the energy of stress waves decreases with increasing temperature, but when the temperature reaches 82.05℃, the energy of stress waves increases with temperature.