The present disclosure relates to a user data processing apparatus and method, and a system. In the user data processing apparatus disclosure, an interface management unit receives user data; at least two service units process the user data, where the at least two service units include a session unit and at least one of a bearer unit, a service flow unit, or a content unit; the interface management unit determines the session unit configured to process the user data, and sends the received user data to the determined session unit; and the session unit determines another service unit configured to process the user data. After receiving the user data, the GW-U determines the service unit configured to process the user data, and processes the user data by using the service unit determined by the GW-U. This improves processing flexibility of the GW-U.