For a certain resonator,it is necessary to find out the optimum position of the laser rod to achieve maximum output power.By using the matrix theory,effect of g-parameters for different laser cavity and different laser rod position on the operation of a thermal insensitive solid state laser resonator is presented.In the condition as 1000 V bump votage at 10 Hz repetition frequency with the crystal in the middle of the resonator,the experimental results seem quite similar with theoretical prediction by using matlab software.The conclusions are of benefit to the design of resonator.