A method, apparatus and system for cell handover in the communication system supporting Carrier Aggregation (CA). The method includes: after receiving a performance measurement report for one or more neighboring cells from the served terminal, according to the performance measurement report, and basing on the CA mode for one or more candidate BSs corresponding to the one or more neighboring cells, a source Base Station (BS) in a communications system selects an algorithm suitable for the CA mode to calculate the priority levels of the one or more candidate BSs; from the one or more candidate BSs, selecting the BS having the highest priority as a target BS; and selecting one more cells to access from all cells being subject to the target BS in the one or more neighboring cells.