Switching method and switching device under multi-carrier aggregation scene

The invention provides a switching method and a switching device under a multi-carrier aggregation scene. The switching method comprises the following steps of: transmitting a request message to a target base station by a source base station, wherein the request message carries a recommended target carrier, an encryption parameter of the recommended target carrier and a corresponding new encryption key KeNB* of the recommended target carrier; receiving a request response message by the source base station, wherein the request response message carries an encryption carrier indicator and an encryption parameter of the encryption carrier; and retransmitting the encryption carrier indicator and the encryption parameter of the encryption carrier to UE (User Equipment) by the source base station, thereby ensuring the consistency of the used safe key between the UE and a base station.