Embodiments of this application provide a multi-channel beamforming method and apparatus. The method includes: determining a target downlink positive polarization beam and a target downlink negative polarization beam based on M preset weight sets, where each weight set includes a phase weight set and an amplitude weight set, different weight sets include a same amplitude weight set, different weight sets include different phase weight sets, and both a quantity of phase weights in the phase weight set and a quantity of amplitude weights in the amplitude weight set are determined based on a quantity of a plurality of channels, where M is an even number greater than 0; and obtaining a target downlink signal based on the target downlink positive polarization beam and the target downlink negative polarization beam.