In the research and development of target tracking, vision-based target tracking technology still has the problems of low accuracy and high cost. This paper designs a tracking system that uses a four-wheel differential mobile chassis as a carrier and uses the 36H11 series tags in Apriltag as a moving target. STM32F103 single-chip microcomputer is used as the core of motion control, and the classic PID control algorithm is used to adjust the wheel speed to achieve target tracking. STM32F765 single-chip microcomputer is used as the image processor of the OV7725 camera to solve the label information. The experimental results show that the Apriltag tag target can be better tracked when the PID parameters are adjusted properly. It can achieve near real-time tracking effect when the tag moving speed is slow, and it can move to the specified position quickly when it is far away from the target.