RRC (Radio Resource Control) connection reestablishment method and device in carrier aggregation

The invention provides RRC (Radio Resource Control) connection reestablishment method and device in carrier aggregation. The method comprises the step that user equipment (UE) performs RRC connection reestablishment according to a parameter on a component carrier, which is specified by a service base station, or by selecting a parameter on a corresponding component carrier according to a preset strategy. The invention initiates the RRC connection reestablishment according to the selected unique parameter to overcome the problem of the prior art that the RRC connection reestablishment in a carrier aggregation cell cannot be established effectively because T311, PCI (Peripheral Command Indicator), C-PNT1, and other parameters have ambiguity when LTE (Line Terminator Equipment)-A UE which simultaneously works on a plurality of component carriers initiates the RRC connection reestablishment.