Based on some relevant theories of robotics such as trajectory planning, the forward and inverse kinematics solutions and DH convention, this paper proposes a new approach towards testing the physical prototype. The approach sets up a 3-D model for a 6-DOF welding robot , works out the simulation results of expected processing trajectory planning for six rods in MATLAB, verifies the trajectory simulation results with the built-in Robot Toolbox of MATLAB, And controls the robot to draw a circle with the ACR9000 motion controller.