Embodiments of the present invention disclose an ACK/NACK feedback method in a wireless communication system, including: determining, by a UE, number of public sub-frames, all of which are uplink sub-frame in PCC and any SCC sub-frames of any radio frame in frame structure configurations according to the frame structure configurations of the PCC and any SCC; selecting, by the UE, a configuration, uplink sub-frames of which merely include sub-frames corresponding to the determined number of public sub-frames from existing seven kinds of frame structure configurations; and feeding back, by the UE, to a eNB ACK/NACK information corresponding to PDSCH in the SCC on the PCC adopting a timing relationship between the PDSCH and the ACK/NACK corresponding to the selected configuration. With the ACK/NACK feedback method of the present invention, the UE may adaptively feed back the ACK/NACK according to the configured frame structure configuration of the CC, the carrier aggregation between Bands of different frame structure configurations is effectively supported and the coexistence and performance optimization of different communication systems is implemented without limiting the number of amplifiers of the UE.