In terms of presetting the unmanned aerial vehicle (UAV) formation order in the bearing-based circumnavigation tracking control algorithm, this paper puts forward with a label-free bearing-based collision avoidance control algorithm for tracking and surrounding a moving target. UAVs can use the separation angle with their pre-neighbor to achieve tracking around a moving target. This neighbor allocation strategy ensures that UAV formations can effectively encircle and surround a moving target regardless of internal number variations. Due to this method, only the closer neighbor among the pre-neighbor and next-neighbor is required as the target for collision avoidance. Finally, the effectiveness of the control algorithm proposed in this paper is verified by numerical simulation experiments.