Abstract: To study the influence of radio frequency (RF) power of LD pumped Nd: YVO₄ acousto-optic Q-switch on diffraction efficiency, by adjusting the RF power applied on the Q-switch, the changing trend of the light leakage and the rise time of the laser pulse was obtained and analyzed. The results show that the leakage light completely disappears when the RF power increases to 4.4W, and the leakage power is less than 500mW when the RF power is between 2W~3W. And the rise time of laser pulse is 60%~70% of the time to reach the first threshold. In summary, not only the rise time of the outputted laser pulse train is considered after the door signal is turned on, but also the light leakage power of the laser is kept as low as possible when the Q-switch is set at the so-called hold-off status. The research results have good reference value for the construction of an acousto-optic Q-switched solid-state laser that can be turned on quickly and have a serious thermal effect.