We report an efficient nanosecond optical parametric generator (OPG) with a periodically-phase-reversed periodically poled MgO:LiNbOs(ppr-PPMgLN), which produces two pairs of signal and idler waves. The OPG is pumped by a 1.064 pm Q-switched Nd-.YVO4 laser. When the repetition rate is set at 10kHz, the maximum average total output power of 570mW is achieved, including 410mW of dual-signal radiations and 160mW of dual-idler radiations. The total conversion efficiency is 32.5%. The tunable dual-signal wavelengths in the range of 1.474-1.518 fim and 1.490-1.539 [xm and the dual-idler of 3.826-3.558 pm and 3.726-3.451 pm are obtained by changing the crystal temperature from 30°C to 200°C.