Laser pulse is quickly deflected by LiNbO3 electro-optics deflector which is driven by avalanche transistor pile, thus a stable laser pulse output ( the pulse width is ns in scale) is gained, the instability of which is decreased from 10%(RMS) to 4%(RMS)compared with the single-longitudinal-mode Q-switched laser pulse output of the oscillator. It indicates that the amplitude stability of shaping laser pulse is improved greatly.