The invention discloses an unmanned aerial vehicle detection method based on the periodicity of a downlink signal of an unmanned aerial vehicle. The method comprises the steps of firstly collecting adownlink communication radio frequency signal between the unmanned aerial vehicle and a remote controller; filtering the downlink radio frequency signal, firstly filtering the signal of a non-unmannedaerial vehicle downlink frequency band, conducting low-pass filtering, and according to whether the amplitude of the filtered signal exceeds a threshold value, obtaining the time when the unmanned aerial vehicle transmits the radio frequency signal, thereby extracting the standard period and the standard signal empty ratio of the unmanned aerial vehicle transmitting the radio frequency signal; finally collecting the radio frequency signal in the environment, and performing filtering processing to determine whether the period of the filtered radio frequency signal and the signal empty ratio match the standard period and the standard signal empty ratio, thereby achieving the detection of the unmanned aerial vehicle periodically transmitting the downlink signal. The method has a great application value.