Abstract: We present a four-rod series resonator CW Nd:YAG laser for the requirement of industrial application in this paper. The symmetrical resonator laser has been developed and is rated at 2 105 W output power with beam parameter product of 24 mm·mrad. The system's total electro-optics efficiency of lamp pumped YAG crystal is as high as 3.5%. The main factors which affect operation of high power solid-state laser module are different positions and thermal focal lengths of crystal rods, and so on. These factors are theoretically analyzed. Conclusions are drawn that the resonator would have the biggest steady range when the rods in it are symmetrically arranged and thermal focal lengths of the rods being not matched can be compensated by adjusting input power of laser system.