Based on reasonable designing,precise temperature controlling of the Cr⁴⁺∶YAG,Nd∶GdVO₄ and LD,passively Q-switched infrared laser was obtained with average output power of 70 mW,pulse duration of 22 ns,repetition rate of 14 kHz,and peak power of 230 W. Then by a piece of type-Ⅱ critical phase matching KTP crystal for extra-cavity and for the system of telescope second-harmonic generation,green laser at 532 nm was achieved with average power of 28.8 mW,pulse duration of 19ns,and peak power of 108 W. The effect of small beam radium was also discussed.