A communication method and a related device, the method including receiving a radio access capability of a terminal device, detecting whether a target radio access capability the same as the received radio access capability of the terminal device exists in a terminal device access capability set, where the terminal device access capability set is a set of radio access capability information corresponding to radio access capabilities, and, when the target radio access capability exists in the terminal device access capability set, indexing second access capability indication information in a context of the terminal device to radio access capability information corresponding to the target radio access capability.