A tunable single frequency non-planar ring oscillator laser is studied. The output power of the 1064 nm single frequency laser is 1.254 W and the slope efficiency is 51.5%. The power stability is ±0.8% within 1 h. The beam qualities of two orientations are measured, which shows the beam quality factors are M2x=1.16 and M2y=1.05, respectively. The laser linewidth is less than 2 kHz measured by beat frequency measurement method. Besides, the frequency tuning of the single frequency laser is also studied by adjusting the temperature of the crystal. The maximum tuning range is about 18 GHz with a tuning coefficient of -2.9 GHz/℃. Meanwhile, the short-term frequency stability is obtained by self-beat-frequency method. The results show that the short-term frequency stability is 4.7×10-12 within 100 ms integral time.