The U shape cavity is used in end pumped Nd∶YAG/LBO SHG configuration is reported.The thermal effect was reduced greatly by modulating the LD and using suitable duty cycle,when the incident power is 8.05 W,repetition rate is 1 kHz,1.38 W TEM00 mode green laser with pulse width 8 ns is obtained by optimization of the system.The optical to optical conversion is 17% and the peak power is up to 172 kW.M2 coefficient is 1.3.