Abstract: Underground monitoring and control system is usually fixed and has limited range, so it is difficult to fully meet dynamic monitoring requirements of underground safety production. Moreover, due to limited wireless communication distance, underground single unmanned aerial vehicle has weak monitoring ability. For the above problems, an underground unmanned aerial vehicles cluster system for monitoring was proposed. The key technologies of the system implementation were introduced in detail such as cooperative control for flying and avoidance, data chain networking, creation of mine roadway environment maps, attitude and position estimation for unmanned aerial vehicles, moving obstacle detection and path planning. Ground dispatching center issues dispatching orders to the underground unmanned aerial vehicles cluster through gateway node set up in underground monitoring sub-station, and the underground unmanned aerial vehicles formation fly with "one" shaped queue along underground roadway. After entering the target area, the unmanned aerial vehicles can monitor the underground target area through the video sensors and environmental monitoring sensors on board, and transmit the monitoring video information and environmental parameters to the underground monitoring sub-station through the cooperation of multiple unmanned aerial vehicles, so as to realize autonomous and dynamic monitoring of the underground target area. The unmanned aerial vehicles cluster system has advantages of wide coverage and strong monitoring capability,through collaborative control, which can effectively improve monitoring efficiency. In addition, it can also solve the problem of limited wireless communication distance of single platform of underground unmanned aerial vehicle by means of wireless multi-hop, which is conducive to transmission of monitoring and control information.