Abstract: In recent years, the bio-inspired intelligent optimization has always been a very popular field of study in intelligence computing and has been widely applied in life science, system science, control science, computer science, management science, sociology and other subjects. The pigeon-inspired optimization (PIO) algorithm is a swarm intelligent optimization algorithm that proposed in recent years, which is inspired by the autonomous homing behavior of pigeons in nature. In this paper, the nature of the pigeons mechanism and flock optimization basic principles are described, and the latest developments of flock optimization model were introduced. The typical applications of unmanned aerial vehicle (UAV) formation, control parameter optimization and image processing were reviewed. Finally, the future development direction was forecasted.