A method for controlling access to a core network, characterized in comprising: determining, by a second serving radio access network node that provides services for a user equipment after a cell change or handover, that a change occurs in access control information for controlling the user equipment in a cell dedicated channel, CELL_DCH, state to access the core network, wherein the access control information comprises at least one of core network domain access control, DSAC, information, paging permission access control, PPAC, information, and registration access control information of a public land mobile network, PLMN, currently selected by the user equipment; and sending, by the second serving radio access network node, radio resource control, RRC, signaling to the user equipment through a dedicated control channel, DCCH, wherein the RRC signaling is used to notify the user equipment that the change occurs in the access control information, so that the user equipment updates the access control information according to the RRC signaling, wherein the determining comprises: receiving a relocation request message sent by a first serving radio access network node that provides services for the user equipment before a cell change or handover, or a core network node to which the first serving radio access network node is connected, wherein the relocation request message includes a global core network identity of the core network node to which the first serving radio access network node is connected; and determining that the change occurs in the access control information for controlling the user equipment to access the core network according to a difference between the global core network identity of the core network node to which the first serving radio access network node is connected and a global core network identity of the core network node to which the second serving radio access network node is connected. determining, by a second serving radio access network node that provides services for a user equipment after a cell change or handover, that a change occurs in access control information for controlling the user equipment in a cell dedicated channel, CELL_DCH, state to access the core network, wherein the access control information comprises at least one of core network domain access control, DSAC, information, paging permission access control, PPAC, information, and registration access control information of a public land mobile network, PLMN, currently selected by the user equipment; and sending, by the second serving radio access network node, radio resource control, RRC, signaling to the user equipment through a dedicated control channel, DCCH, wherein the RRC signaling is used to notify the user equipment that the change occurs in the access control information, so that the user equipment updates the access control information according to the RRC signaling, wherein the determining comprises: receiving a relocation request message sent by a first serving radio access network node that provides services for the user equipment before a cell change or handover, or a core network node to which the first serving radio access network node is connected, wherein the relocation request message includes a global core network identity of the core network node to which the first serving radio access network node is connected; and determining that the change occurs in the access control information for controlling the user equipment to access the core network according to a difference between the global core network identity of the core network node to which the first serving radio access network node is connected and a global core network identity of the core network node to which the second serving radio access network node is connected. receiving a relocation request message sent by a first serving radio access network node that provides services for the user equipment before a cell change or handover, or a core network node to which the first serving radio access network node is connected, wherein the relocation request message includes a global core network identity of the core network node to which the first serving radio access network node is connected; and determining that the change occurs in the access control information for controlling the user equipment to access the core network according to a difference between the global core network identity of the core network node to which the first serving radio access network node is connected and a global core network identity of the core network node to which the second serving radio access network node is connected.