Embodiments of the present disclosure disclose an access method, which comprises: establishing a first connection between a user equipment and a first mobile communication network according to a first subscriber identification number; requesting, via the first connection, a server to assign a subscriber identification number to the user equipment, wherein the subscriber identification number is a subscriber identification number corresponding to a SIM card in the server, and the subscriber identification number is a subscriber identification number at a location where the user equipment is currently located; acquiring, via the first connection, the second subscriber identification number assigned by the server; and establishing a second connection between the user equipment and a second mobile communication network servicing the current location according to the second subscriber identification number. According to the embodiments of the present disclosure, the roaming communication fees are reduced, and the communication quality is improved.