A core network node may send an overload indicator capable of distinguishing PLMNs to an access network node when the core network node is overloaded; and the access network node may learn a PLMN over which access control needs to be performed according to the overload indicator received. PLMNs are distinguished in access control according to an actual situation of overload of the network node caused by a PLMN sharing the network, ensuring fairness in access control over terminals of all PLMNs sharing the network.