An optical parametric oscillator (OPO),which is pumped by a Nd:YVO4 laser with the 1064 nm wavelength,is obtained based on PPMgLN.For the continuous wave (CW) operation mode,the threshold is only 1.1 W and the output power of idler at 3.2 μm is 905 mW.For the active Q-switched operation mode,the average output power at mid-infrared wavelength is 1.13 W,which corresponds to an optical-optical conversion efficiency of 17%.For the passively Q-switched operation mode with a Cr:YAG saturable absorber in the cavity of Nd:YVO4 laser,the average output power of idler from OPO at the mid-infrared wavelength is 125 mW.By changing the periods of the domain structure on the PPMgLN wafer,a widely tunable mid-infrared spectrum from 3.13to 4.20 μm is obtained.