Disclosed are a method for implementing HARQ feedback, and a method and device for allocating an uplink subframe. The method is: determining a TDD uplink/downlink reference configuration used for FDD PDSCH HARQ feedback, and allocating, according to the number of uplink subframes indicated by the TDD uplink/downlink reference configuration in a radio frame, an FDD downlink subframe corresponding to ACK/NACK information borne by an uplink subframe indicated by the TDD uplink/downlink reference configuration to the uplink subframe, so that numbers of FDD downlink subframes corresponding to ACK/NACK information borne by the uplink subframes indicated by the TDD uplink/downlink reference configuration are approximately equal. In this way, ACK/NACK information corresponding to downlink data can be timely and accurately fed back, so as to perform accurate data retransmission, thereby effectively ensuring the system performance.