A link identifier indication method includes: A multi-link device working on a plurality of links sends a radio frame, where the radio frame includes link information of at least one link in the plurality of links, and link information of one link is used to indicate the link and corresponds to a link identifier of the link; a receiving device that receives the radio frame may determine the link identifier of the link corresponding to the link information, so that in communication of the multi-link device, a link can be identified by using the link identifier.