Embodiments of this application provide a method and an apparatus for determining radio channel multipath information and a related device. A server obtains reference signal received powers of a plurality of downlink beams, and determines a path angle and path strength of a propagation path from an antenna in a power angular spectrum cell indicated by each power angular spectrum cell identity to a grid indicated by each grid identity, based on an association relationship between the reference signal received powers of the plurality of downlink beams and the following: a grid identity, a serving cell identity, and a power angular spectrum cell. The server can determine the radio channel multipath information based on the reference signal received powers of the plurality of downlink beams, instead of depending on map and engineering parameter information. This helps improve accuracy of the radio channel multipath information.