A communication method, comprising: receiving (S201A), by a mobility management network element, first information from a terminal device, wherein the first information comprises a globally unique temporary identity, GUTI, of the terminal device and private-network information, or the GUTI of the terminal device and public-network information, or a SUPI of the terminal device in the public network and/or a SUPI of the terminal device in the private network; obtaining (S202A), by the mobility management network element, a user equipment context of the terminal device registered in a public network and a user equipment context of the terminal device registered in a private network based on the first information by: sending, by the mobility management network element, request information to a data management network element of the private network based on the first information; receiving, by the mobility management network element, subscription data of the terminal device in the private network from the data management network element of the private network; and creating, by the mobility management network element, the user equipment context of the terminal device in the private network based on the subscription data in the private network; and using (S203A), by the mobility management network element, a combination of the user equipment context of the terminal device in the public network and the user equipment context of the terminal device in the private network as a user equipment context of the terminal device, wherein the combination comprises public information common in the user equipment contexts of the terminal device in the public and in the private network, specific information of the user equipment context in the public network, and specific information of the user equipment context in the private network. receiving (S201A), by a mobility management network element, first information from a terminal device, wherein the first information comprises a globally unique temporary identity, GUTI, of the terminal device and private-network information, or the GUTI of the terminal device and public-network information, or a SUPI of the terminal device in the public network and/or a SUPI of the terminal device in the private network; obtaining (S202A), by the mobility management network element, a user equipment context of the terminal device registered in a public network and a user equipment context of the terminal device registered in a private network based on the first information by: sending, by the mobility management network element, request information to a data management network element of the private network based on the first information; receiving, by the mobility management network element, subscription data of the terminal device in the private network from the data management network element of the private network; and creating, by the mobility management network element, the user equipment context of the terminal device in the private network based on the subscription data in the private network; and sending, by the mobility management network element, request information to a data management network element of the private network based on the first information; receiving, by the mobility management network element, subscription data of the terminal device in the private network from the data management network element of the private network; and creating, by the mobility management network element, the user equipment context of the terminal device in the private network based on the subscription data in the private network; and using (S203A), by the mobility management network element, a combination of the user equipment context of the terminal device in the public network and the user equipment context of the terminal device in the private network as a user equipment context of the terminal device, wherein the combination comprises public information common in the user equipment contexts of the terminal device in the public and in the private network, specific information of the user equipment context in the public network, and specific information of the user equipment context in the private network.