Embodiments of this application provide a positioning method, an apparatus, and a system, to resolve a problem that high-accuracy positioning cannot be implemented based on existing assistance data. The method includes: a location management device obtains a plurality of assistance data from one or more access network devices, where each assistance data includes one or more groups of mapping relationships corresponding to one or more preset angles, and each group of mapping relationships includes a mapping relationship between each of one or more PRS resource identifiers and power information corresponding to each PRS resource identifier at a corresponding preset angle; the location management device obtains, from a terminal device, power information corresponding to one or more PRS resource identifiers at each of a plurality of to-be-measured angles; and the location management device positions the terminal device based on the plurality of assistance data and the power information.