Embodiments of the present disclosure relate to a data transmission method, user equipment, and a control plane node. User equipment (UE) determines a security attribute of a session of the UE; the UE sends a session establishment request message to a control plane node when the security attribute of the session of the UE does not meet a security requirement of an application. The session establishment request message is used to request to establish a session corresponding to the security requirement of the application. Embodiments of the disclosed method reduce an unnecessary signaling exchange caused by establishment of a new session in a data transmission process to facilitate meeting requirements of different services.