Based on periodically poled L iNbO3 doped withMgO, the theoretical and experimental study on temperature-tuned signal-resonanted quasi-phase-matched op tical parametric oscillator (QPM2OPO ) is described. A LD pumped acousto-optically Q-switched Nd: YAG laser is used as a pump source and the OPO generates signal wave-lengths tunable in the range of 1561～1672nm, the maxmium signal output power is 297mW at an average incidentpump power of 1. 728W.