The invention relates to an unmanned aerial vehicle used for intrusion early warning. The unmanned aerial vehicle comprises an unmanned aerial vehicle body, wherein the unmanned aerial vehicle body carries a video monitoring device through a cradle head device; the video monitoring device comprises a video capture unit, a wireless transmission unit and a power supply unit used for supplying the power to the video capture unit and the wireless transmission unit; the video capture unit is connected to the wireless transmission unit; the video capture unit comprises at least one high-definition camera, a video encoder connected to the high-definition camera and an adaptive light filling device capable of automatically filling the light according to the video capture need; the high-definition camera is provided with a lens device; and the video encoder is connected to the wireless transmission unit. According to the unmanned aerial vehicle used for intrusion early warning, the unmanned aerial vehicle carrying the video monitoring device cruises above a to-be-monitored area, so that aerial monitoring and early warning can be carried out on the to-be-monitored area.