Diffraction beams produced by an acousto-optic modulator are widely used in various optical experiments, some of which need to modulate the radio-frequency drive signal to change the diffraction beams from continuous light to pulsed light. The generation of such pulsed light is open-loop, and long-term stability of the power is disregarded. In this paper, we introduce a method to suppress the pulsed light power drift of a semiconductor laser. By using the servo system, the low frequency power drift of 1-60 kHz pulsed light can be suppressed. This pulsed light power stabilization method can be applied to optical rotation detection and pulse pumping.