The invention discloses a single base station unmanned aerial vehicle positioning system and landing guidance method, based on an ultra wide band (UWB) technology. The single base station unmanned aerial vehicle positioning system includes an unmanned aerial vehicle, an airborne positioning label and a guide base station, wherein the guide base station is arranged at a certain determined locationat an unmanned aerial vehicle landing platform; the guide base station can measure the distance d between the base station and the airborne positioning label, and can also measure the azimuth Phi andthe pitch angle Theta of the airborne positioning label, relative to the guide base station; the sensing radius of the guide base station is R; when the unmanned aerial vehicle enters the sensing radius range of the guide base station, the guide base station measures the distance d between the local machine and the airborne positioning label carried by the unmanned aerial vehicle; the guide base station and the airborne positioning label acquire the azimuth Phi and the pitch angle Theta of the label, relative to the guide base station, through an array antenna; the base station transmits the measured d, Phi, and Theta to the label carried by the unmanned aerial vehicle through an UWB signal; the label obtains the three-dimensional relative coordinates of the local machine relative to the base station at this time, determines the forward direction of the unmanned aerial vehicle, and feeds the information back to an unmanned aerial vehicle flight control module; and the unmanned aerial vehicle flight control system instructs the unmanned aerial vehicle to land safely and accurately on the specified landing platform.