The present invention discloses a method for uplink synchronization control, wherein network side and a user equipment (UE) maintain a timing alignment timer (TAT) for the UE, and maintain an uplink transmission timing adjustment amount for uplink component carriers, and the method includes following steps: the network side measuring uplink component carriers of the UE, and obtaining an uplink transmission TA amount of the uplink component carriers; and before the TAT expires, the network side transmitting to the UE an adjustment command comprising information of the uplink transmission TA amount for at least one of the uplink component carriers of the UE. Also disclosed in the embodiments of the present invention are a method for uplink synchronization control at the UE side, and a base station and a UE for implementing the above methods. The solution of the present invention enables accurate adjustment of the uplink synchronization for each component carrier in a carrier aggregation mechanism.