Unmanned aerial vehicle (UAV) has good stealth characteristics, strong penetration ability, low acquisition cost and flexible use, which is used by criminals or terrorists organizations to perform intelligence collection and ground attack tasks. Especially in urban environment, the effect is far better than that of traditional ground attack methods. This kind of asymmetric attack may have a huge negative impact on social security and stability, national economic development and military strength construction. Small UAV has become a new threat to safeguard national interests. The main characteristics of current small UAV is analyzed, combined with the typical threat cases of small UAV in recent years, the development ideas of future anti UAV electro-optical technology is proposed.