The computer simulationand experimental results of diode pumped high-repetition-rate Nd:YAG laser are reported. According to the calculations andthe experimental results, the parameters of components were determined. By using KD*Pcrystal for E-O Q-switching, an 8 ns Q-switched laser pulse output of 35 mJ was obtainedunder pulse repetition rate of 200 Hz. By using KTP crystal for SHG, the double frequencylaser output of 20 mJ at 7 ns pulse width was realized. Furthermore, the design principlesand structures of the laser are also introduced.