Embodiments of this application disclose a beamforming weight calculation method, including: determining X sub resource block groups, where one of the X sub resource block groups includes a part of a resource block group, all resource block groups in each sub resource block group are occupied by a user, and X is a positive integer greater than 1; determining, based on the X sub resource block groups, a beamforming weight calculation method used for each sub resource block group, where the beamforming weight calculation method includes normalized-eigen beamforming or power limited-eigen beamforming; and obtaining, based on the beamforming weight calculation method corresponding to each sub resource block group, a beamforming weight corresponding to the sub resource block group. For each sub resource block group, a corresponding beamforming weight calculation method is adaptively determined, and a corresponding beamforming weight is obtained. This effectively improves a power utilization ratio of downlink data sending in a communications apparatus, effectively improves spectral efficiency of a cell, and improves an average throughput of the cell.