Provided are a method and a base station for controlling mobility of UE. The method may include receiving, by a CU, a measurement report from a UE through a DU; sending, by the CU, a UE context setup request message to a target DU to create a UE context and set a bearer up; sending, by the target DU, a UE context setup response message to the CU to inform the CU of completion of creating the UE context and setting up a bearer; sending, by the CU, a UE context modification request message including a RRC connection reconfiguration message to the source DU; performing, by the target DU, a random access procedure with the UE; and forwarding, by the target DU, an RRC connection reconfiguration complete message received from the UE to the CU.