Disclosed are a HARQ-ACK feedback method, a HARQ-ACK extraction method, a base station, and a user equipment. The Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) feedback method is performed by a base station, and used to feed back corresponding HARQ-ACKs to a plurality of user equipments. The method includes: generating, by employing a plurality of HARQ-ACKs corresponding to the plurality of user equipments, at least one piece of downlink control information, where for each user equipment, an implicit mapping relationship exists between the user equipment and one or more information bits of the downlink control information; and transmitting to the plurality of user equipments the downlink control information.