Embodiments of the present invention provide a terminal registration method, device, and system, and relate to the field of communications technologies, so as to ensure that a terminal determines in time whether registration is successful, and save network resources. The method includes: starting, by an access point device, monitoring on a monitored resource when the access point device receives an access request message sent by a terminal; and after the terminal sends a registration request message to a database, if the access point device receives, when the monitored resource monitored by the access point device does not reach a monitoring threshold, a registration response message sent by the database, stopping the monitoring on the monitored resource. Embodiments of the present invention are used for terminal registration.