A method includes obtaining, by a terminal, a quantity M of beamforming vectors needing to be reported by the terminal and a first reference signal that are sent by a base station; estimating downlink channel states on N dual-polarized antenna ports based on the first reference signal; selecting m first beamforming codewords based on the downlink channel states and the quantity M of beamforming vectors needing to be reported that is sent by the base station; and feeding back the m selected first beamforming codewords and ranks of the downlink channel states to the base station.