For the UAV formation control problem, a UAV formation controller is proposed. The formation controller is designed by the sliding mode control method under the Leader-Follower structure. The formation controller enables the UAV formation to achieve the desired formation, while the following UAVs can track the reference trajectory of the leading UAV. A formation algorithm verification platform is built, which consists of three quadrotor UAVs, UWB positioning system, communication system, and ground control station. The controller is simulated by MATLAB simulation software, and the flight experiment is carried out through the formation algorithm verification platform, which verifies the effectiveness and feasibility of the formation controller based on the Leader-Follower method.