Abstract: Influence of position of output mirror on beam of three-rod solid-state laser has been analysed by means of matrix optics,it gives the stability zone by investigating two types of resonator.The result show that the stability zone the mode volume and out power of three-rod solid-state laser are affected by the position of out put mirror.The mode volume and output power of equal interval resonatos are larger than the other resonators,which is better than the symmetric resonator.The facula radius ω_0 and the f...