A method, an apparatus, a UE, and a base station for transmitting a HARQ-ACK are disclosed. The method includes: determining a channel for transmitting a HARQ-ACK; determining a HARQ-ACK feedback bit; and sending the HARQ-ACK feedback bit on the channel. According to this application, transmission of a HARQ-ACK between a UE and a base station can be implemented in a scenario where carrier aggregation is performed between base stations having a non-ideal backhaul.