To obtain high power 589-nm yellow laser, a T-shaped thermal-insensitive cavity is designed. The optimalpower ratio of 1064- and 1319-nm beams is considered and the fundamental spot size distribution from theoutput mirror to the two laser rods are calculated and simulated, respectively. As a result, a 589-nm yellowlaser with the average output power of 5.7 W is obtained in the experiment when the total pumping poweris 695 W. The optical-to-optical conversion efficiency from the fundamental waves to the sum frequencygeneration is about 15.2% and the pulse width is 150 ns at the repetition rate of 18 kHz. The instabilityof the yellow laser is also measured, which is less than 2% within 3 h. The beam quality factors are M_x^2 =4.96 and M_v^2 = 5.08.
