The invention discloses a tracking and positioning system based on optical encoding and a method. The invention relates to the technical field of unmanned aerial vehicles and application thereof. The provided detection system is capable of automatically tracking the positions of police/security personnel and providing the surrounding state. The system comprises an unmanned aerial vehicle platform which is small and lightweight, and has the advantage of easy deploying/recycling. The work height of the unmanned aerial vehicle platform is suitable for urban environments. According to the technical scheme provided by the invention, the tracking and positioning system based on optical encoding comprises a tracking platform, a navigation platform and an information terminal; and the tracking platform is a four-axis unmanned aerial vehicle which carries different modules according to task needs, and comprises an optical tracking module, an information processing module, a sensor module, an electromechanical control module and a communication module. The system and method are mainly used in unmanned aerial vehicle applications.