To evaluate the flight safety threat of UAV to other aircrafts in the air, experiments and numerical simulations of UAV impacting the aircraft structure must be carried out. Based on the launch test system of large caliber special-shaped air cannon developed for the first time in China, this paper carried out collision experiments between a light UAV and the flat tail of a typical airliner, established the corresponding finite element numerical simulation model of UAV impacting on the flat tail by using LS-DYNA software, and compared calculation results of the flat tail dynamic responses and damage morphologies with experimental results. The good consistency between them indicates the rationality of the numerical simulation method. On this basis, the numerical simulation method is used to study the effects of UAV attitudes on the impact damage of the flat tail. The results show that the UAV impact is easy to cause penetrating damage to the leading edge of the flat tail, the pitching and rolling attitudes have a few effects on the impact damage of the flat tail, and the heading attitude has a greater effect, and the UAV battery has the risk of invading the interior of the flat tail and causing explosion and fire during the impact process.