A high power narrow linewidth tunable 1 064 nm laser is obtained using three mirror ring cavity with an etalon. Theoretical analysis of unidirectional operation of the ring resonator, narrowing linewidth and tuning wavelength with an etalon and large volume mode operation of the laser was carried out. The mirror curvature and output coupling ratio were optimized in the experiment. Under the 808 nm laser diode pump power of 151 W, 33.7 W of unidirectional 1 064 nm laser output was obtained with beam quality factor of 1.28 and linewidth of 0.1 GHz, and the corresponding optical conversion efficiency was 22.3%. Precise tuning of laser wavelength was realized by controlling precisely temperature of the etalon. Tunable range of 72.6 GHz was achieved by varying the temperature of the etalon, and the tuning accuracy was 220 MHz. The output power of the 1 064 nm laser was changed by about 10% in wavelength tuning process. The whole system is stable and reliable, relatively simple and easy to realize. It provides a practical and effective technical mean for obtaining tunable narrow linewidth 1 064 nm laser.