The embodiment of the invention provides a registration authentication method, a server, terminal equipment and a readable storage medium, which are applied to an LwM2M system, and can realize that the server receives a registration request sent by the terminal equipment and registers the terminal equipment according to the registration request; the server sends a response message of the registration request to the terminal device, wherein the response message is used for notifying the terminal device that registration is completed on the server; the server sends a query request to the terminal equipment, the query request is used for querying the registration state of the terminal equipment, if the terminal equipment receives a response message of the registration request, the registration state of the terminal equipment is registration success, and otherwise, the registration state of the terminal equipment is registration failure; and the server determines the registration state ofthe terminal equipment according to the query result corresponding to the query request. In other words, in the embodiment of the invention, when registration of the terminal equipment fails, the server can discover the registration failure in time, and the registration success rate of the terminal equipment is improved.