In this paper, a kind of AO Q switched Nd:YAG laser with one oscillator and one amplifier is studied. The oscillator and the amplifier are composed of two Nd:YAG rod pumped by Krypton lamp and one AO modulator. The maximum average output power is 169 W. Under the condition of repetition rate 1 kHz, the pulse width is 70 ns, and the maximum peak power is 594 kW. The laser beam is delivered by an all silica fiber with diameter of 0.6 mm and focused by a group of lenses with new designed. A large scale laser deep engraving is realized.