Trajectory tracking is a critical issue in the field of mobile robotics. This paper aims to design and implement a backstepping PID controller for trajectory tracking of a differential drive-wheeled mobile robot, evaluating the practical performance of this controller. Initially, we design and construct the robot. We then develop detailed kinematic and dynamic models for the robot and create a controller that integrates backstepping and PID techniques based on these models. A simulation model based on the actual parameters of the robot is subsequently developed. Finally, experiments are conducted to validate the effectiveness of the proposed controller. The experimental process involved a circular trajectory with a radius of 1.5 m, resulting in minimal orbital errors ranging from –0.01 m to 0.01 m. These results confirm the effectiveness of the backstepping PID controller, demonstrating its practical applicability for mobile robot trajectory tracking.