We address the problem of formation maneuvering control of unmanned aircraft swarm systems with leader-follower structure， and design distributed formation controllers based on bearing information， so as to realize the translation and rotation maneuver control of unmanned aircraft swarms. To overcome the limitations of existing formation control methods based on bearing information when handling time-varying bearing formation， we design a state observer. This observer estimates the desired positions and velocities of the UAVs using relative bearing information from neighboring UAVs and the position and velocity information of the leader. A backstepping controller is designed based on the desired velocities to achieve the maneuver control of the formation system. The estimation error of the observer and the stability of the controller are proven using the Lyapunov method. The effectiveness of the proposed control method is validated through simulations involving translation and rotation maneuvers.