Through reasonable design of LD end pumped Nd∶YAG laser cavity mirror film,laser oscillation of the strongest transition of 1064 nm and the adjacent 1319 nm line were simultaneously suppressed,and single wavelength laser output at 1338nm was achieved successfully.In the experiment,the plane-plane and plane-concave cavities were compared.The output of 1338 nm single wavelength laser at the continuous-wave mode and the acousto-optic Q-switched mode were studied.For continuous-wave mode,the maximum output power of 3.25 W was obtained at the incident pump power of 12.5 W.For the acousto-optic Q-switched mode,both the average output power and pulse width decreased with the reducing of pulse repetition frequency.Under the incident pump power of 12.9 W,the average output power reduced from 2.8 W to 1.9 W when pulse repetition frequency reduced from 15 kHz to 5 kHz,and the corresponding pulse peak power increased from 1.7 kW to 5.4 kW.