Based on the physical conditions of single-frequency operation of lasers, the relationship between the transmissivity of output coupling mirror corresponding to the critical single-frequency operation of high-power laser and the injection pump power is theoretically simulated and analyzed. According to the theoretical simulation results, the output coupling transmissions for the laser with end-pumped single laser crystal and a pump power of 115 W, as well as for the laser with double end-pumped two laser crystals and a total pump power of 240 W, are optimized to be 25% and 37%, respectively. As results, single-frequency continuous wave 1 064 nm lasers with output powers of 51 W and 101 W are realized separately in a single resonator, with respect to the optical-to-optical conversion efficiencies of 45.9% and 42.9%, respectively. Experimental results are consistent with the theoretical expectation.