Abstract: In order to understand the effects of a vertically incident CO₂ laser beam on the tungsten-inert gas(TIG) arc characteristics,the spectra of the arc plasma with the action of a vertically incident laser beam are analyzed.The electron temperature of the arc plasma is calculated by the boltzmann plot method.The results show that the electron temperature of the arc plasma with the action of CO₂ laser beam radiation is increased between the laser acting position and anode zone.The influences of laser power,arc current and laser acted position on electron temperature are also studied.The charges in electron temperature indicate that the inverse bremsstrahlung absorption of laser energy is the dominant factor influencing the electron temperature of TIG arc plasma with the action of CO₂ laser beam.