Embodiments of this application provide a network security management method and an apparatus. The method includes: receiving, by a first network device, a session request sent by a terminal device, where the session request is used to request establishment of a first session with a first data network, the session request includes first authentication information for the first session, and the first authentication information includes identifier information of the first data network; obtaining, by the first network device, second authentication information for a second session of the terminal device, where the second authentication information includes identifier information of a second data network to which the second session is connected; and if the identifier information of the first data network is the same as the identifier information of the second data network, authorizing the terminal device to establish the first session with the first data network.