Abstract: A tunable single frequency 1 319 nm laser was obtained adopting laser diode pumped monolithic non planar ring Nd:YAG resonator. The output power of the 1 319 nm single frequency laser was 99 mW and the slope efficiency is 29%. The longitudinal and transverse modes of the laser were measured using the scanning F P interferometer and the moving slit method respectively. The results showed that the laser operated in the single longitudinal and basic transverse mode. The frequency tuning of the single frequency laser was also studied by adjusting the temperature of the crystal. The maximal tuning range is about 14 GHz with a tuning coefficient of 2 1 GHz/℃.