The present invention provides a cable modem (CM) registration method and apparatus, where the method includes: after obtaining a media access control (MAC) address of a CM, sending, by a cable modem termination system (CMTS), the MAC address of the CM and identification information of the CMTS to an authentication server for performing authentication. By binding the CM to the CMTS, a location in which the CM gets online can be limited, thereby preventing the CM from accessing any CMTS.