The present disclosure relates to session information management methods. One example method includes sending, by a session management function (SMF) network element, identification information of a terminal device, a data network name (DNN), and slice information to a data management network element to request first subscription data that is of the terminal device and that is associated with the DNN and the slice information, where the slice information is used to identify a network slice served by the SMF network element, and receiving, by the SMF network element, the first subscription data from the data management network element.