The application provides a beam training method and a communications apparatus. The method includes: generating, by a terminal device, capability indication information, where the capability indication information is used to indicate that the terminal device can support simultaneous beam training in a maximum of N frequency bands, and N is an integer greater than or equal to 1; and sending, by the terminal device, the capability indication information. In this way, the network device may select a plurality of frequency bands at a time based on a capability of the terminal device to simultaneously perform beam training. Therefore, in an embodiments of this application, when the quantity N, of frequency bands for simultaneous training, supported by the terminal device is greater than 1, beam training may be simultaneously performed between the network device and the terminal device in a plurality of frequency bands.