<b>Autonomous Trajectory Tracking and Contouring Control of Three Dimensional CNC</b> In this study we analyzed a three axes computer numeric control CNC machine. Here improve the trajectory tracking and contouring performance of both linear and circular trajectories of a CNC. This paper introduced an autonomous method for better trajectory tracking and contouring by different position sensors are placed on three axes of CNC machines. So reduce trajectory error and contouring error of CNC machines. This method is best solution for improve the trajectory tracking ability and precision of a CNC machine for both linear and circular trajectories. Computer numerical control CNC , Autonomous, Trajectory tracking, Contour, Contouring error 435-438 Issue-2 Volume-2 Henna A