A key isolation method, comprising: generating, by a macro base station, a key for use in communication of a destination base station with a User Equipment, UE, from a distinguishing parameter of the destination base station and a temporary key shared by the macro base station with the UE, upon deciding user plane bearers of the UE to be handed over; and transmitting, by the macro base station, the distinguishing parameter to the UE so that the UE generates the key for use in communication of the UE with the destination base station from the distinguishing parameter, and the temporary key shared by the UE with the macro base station; wherein the destination base station is a destination local base station; and if the macro base station decides the user plane bearers of the UE to be handed over from the macro base station to the destination local base station or decides the user plane bearers of the UE to be handed over from a local base station where the UE is currently located to the destination local base station, then the method further comprises: transmitting the generated key to the destination local base station; wherein control plane bearers of the UE are not handed over from the macro base station to the destination local base station, and control plane bearers of the UE are not handed over from a local base station where the UE is currently located to the destination local base station; wherein the macro base station has the entire user plane and control plane protocol stacks, and the local base station has the entire user plane protocol stack and a part of the Radio Resource Control, RRC, protocol function. generating, by a macro base station, a key for use in communication of a destination base station with a User Equipment, UE, from a distinguishing parameter of the destination base station and a temporary key shared by the macro base station with the UE, upon deciding user plane bearers of the UE to be handed over; and transmitting, by the macro base station, the distinguishing parameter to the UE so that the UE generates the key for use in communication of the UE with the destination base station from the distinguishing parameter, and the temporary key shared by the UE with the macro base station; wherein the destination base station is a destination local base station; and if the macro base station decides the user plane bearers of the UE to be handed over from the macro base station to the destination local base station or decides the user plane bearers of the UE to be handed over from a local base station where the UE is currently located to the destination local base station, then the method further comprises: transmitting the generated key to the destination local base station; wherein control plane bearers of the UE are not handed over from the macro base station to the destination local base station, and control plane bearers of the UE are not handed over from a local base station where the UE is currently located to the destination local base station; wherein the macro base station has the entire user plane and control plane protocol stacks, and the local base station has the entire user plane protocol stack and a part of the Radio Resource Control, RRC, protocol function. transmitting the generated key to the destination local base station; wherein control plane bearers of the UE are not handed over from the macro base station to the destination local base station, and control plane bearers of the UE are not handed over from a local base station where the UE is currently located to the destination local base station; wherein the macro base station has the entire user plane and control plane protocol stacks, and the local base station has the entire user plane protocol stack and a part of the Radio Resource Control, RRC, protocol function.