This paper presents the strategies and control structures of 4 formation modes for fixed-wing UAV, and formation-keeping simulations under each mode are carried out to compare their characteristics and get the use conditions. Based on 10 kg flat-wing UAV platform, the tight formation flight test of 2–12 aircraft is carried out, formation flight based on flight route, on-line route planning and re-planning, dynamic obstacle avoidance, dynamic target tracking, coordinated attack and other tasks are completed, and good formation flight results are obtained. The 4 modes are verified to be effective and feasible. The flight test results show that the UAV formation modes has fast response, high control accuracy and strong robustness, and can adapt to different mission scenarios.