Abstract: Proceeding from the SI-GaAs's energy level structure, the feasibility of using the ion-implanted GaAs semiconductor material as a passive Q-switched unit of solid-state lasers is discussed. The dynamic characteristic of GaAs used as passive Q-switch device is investigated experimentally.In the experiment, flat-flat cavity was adopted and (Nd∶YAG) was pumped by a xenon lamp,and the Q-switched waveform of 62ns single pulse width was obtained at repetition rate of 1Hz.