Abstract: The spreading experiments of liquid Ga on the surface of quartz glass under different ultrasonic amplitudes were carried out, the CCD photograph recorder was used to observe and record the process. It is found that with the increase of ultrasonic amplitude, the spreading speed and the spreading area increase, accompanied by the atomization phenomenon.The numerical simulation of the growth and rupture of cavitation bubbles in liquid Ga was carried out by solving the motion equation of the cavitation bubble wall in Matlab software. The results show that with the increase of initial radius of the cavitation bubble, the cavitation threshold decreases, and the surface tension of the liquid Ga decreases, the cavitation effect is easy to occur.The increase of the ultrasonic amplitude and initial radius of the cavitation bubble promotes the cavitation effect in the liquid Ga, thereby removing the oxide film on the surface of the liquid Ga and promoting its spreading.