A method for network convergence, comprising: before authentication of an access user is successful, a public service packet data network, PDN, connection for bearing public information being established by a first gateway and the public service PDN connection being used for authentication for the access user, receiving, by a second gateway, a message for establishing an independent PDN connection between the first gateway and the second gateway, wherein the first gateway is the gateway of a first network in which the access user is currently located and the first gateway includes a user end device identifiable to the second network, wherein the second gateway is a gateway of a second network to be accessed by the access user, and wherein a service borne by the independent PDN connection comprises a shared service, and wherein the shared service is a service that does not require the second network to distinguish access users; after the authentication of the access user is successful, receiving (S101), by the second gateway, a PDN connection establishment message corresponding to the access user and establishing, by the second gateway, the PDN connection between the first gateway and the second gateway, wherein the message carries an access user identifier and is sent by the first gateway, and a service borne by the PDN connection corresponding to the access user comprises a private service provided over a network of the access user in the first network; and initiating (S102), by the second gateway, according to the access user identifier, a charging procedure corresponding to the access user. before authentication of an access user is successful, a public service packet data network, PDN, connection for bearing public information being established by a first gateway and the public service PDN connection being used for authentication for the access user, receiving, by a second gateway, a message for establishing an independent PDN connection between the first gateway and the second gateway, wherein the first gateway is the gateway of a first network in which the access user is currently located and the first gateway includes a user end device identifiable to the second network, wherein the second gateway is a gateway of a second network to be accessed by the access user, and wherein a service borne by the independent PDN connection comprises a shared service, and wherein the shared service is a service that does not require the second network to distinguish access users; after the authentication of the access user is successful, receiving (S101), by the second gateway, a PDN connection establishment message corresponding to the access user and establishing, by the second gateway, the PDN connection between the first gateway and the second gateway, wherein the message carries an access user identifier and is sent by the first gateway, and a service borne by the PDN connection corresponding to the access user comprises a private service provided over a network of the access user in the first network; and initiating (S102), by the second gateway, according to the access user identifier, a charging procedure corresponding to the access user. <EOS>