In this paper, a new Cartesian gas cutting robot was designed, which had five servo motors and six stepped motors. Also, we developed a three-torch model and studied algorithm and boundary conditions that were pretty available for three-torch device and experiment verified this theory. A laser height control system was also developed in this robot. And the experiments certified that the model was effective and could be satisfy with the actual industrial needs. Meanwhile, the laser height control system could realize height tracking when the surface of the steel was not flat.