Abstract: This robot simulation system is developed for the beam welding in IVECO car.The kinematic model of RV12l 6R robot is built.The forward and inverse solutions are also given.The 3D graphic simulation of the robot workspace is made. The complex informations of the robot hand positions and poses are expressed by integration of robot hand 、rotate platform and workpiece using 3D modeling technique while the researchs of robot simunation system of many scholars are mainly concentrated on the algorithnm and 2D graphic simulation.It also provides a way for the design of rotate platform.The programming example of crossbeam welding is made.The system has been successfully used in the crossbeam welding on IVECO car.