The invention relates to early warning equipment for vehicles, in particular to a crowd gathering early warning unmanned aerial vehicle. A camera collects samples, and pre-judgment of the crowd intensity and warning are completed through cooperation of a target calibration module, a target track pre-judgment module, a crowd gathering degree prediction module and an early warning judgment module. According to the unmanned aerial vehicle, the camera can be utilized to collect video information; firstly, the video information is compared with a standard characteristic database to determine an accurate target group; then the video information with multiple-frame numbers is processed; the tracks of targets are pre-judged; the track line set of the multiple targets serves as an object; a target area is delimited; pre-judgment of the crowd gathering degree can be achieved as long as the condition of tracks in the target area is obtained; and a pre-judgment value is compared with the crowd intensity standard, and if the pre-judgment value exceeds the standard, early warning is conducted. Thereof, the unmanned aerial vehicle can monitor the situation of the crowd density, make early warning judgment and process the information in time, so that information process delaying is avoided, and prevention is well conducted.