Disclosed are a downlink HARQ feedback method and device, and a terminal and a
base station. The method comprises: sending terminal capability information to a
base station, wherein the terminal capability information comprises first terminal capability information used for indicating that a terminal supports a low-time-
delay service, and second terminal capability information used for indicatingthat the terminal requests the
base station to configure, for the terminal, a target feedback type corresponding to the low-time-
delay service, the target feedback type being used for indicating thatthe terminal uses, when feeding an HARQ result of downlink data back to the base
station, an independent downlink feedback channel configured by the base
station for the terminal; receiving a feedbacktype configured for the terminal and returned by the base
station; and when the feedback type is consistent with the target feedback type, feeding the HARQ result of the downlink data back to the base station via the downlink feedback channel configured by the base station for the terminal. In the present disclosure, a terminal quickly carries out the feeding back of an HARQ result of downlink data by using an independent downlink feedback channel corresponding to a low-time-
delay service, thereby realizing low-time-delay synchronous feedback, and satisfying low-time-delay service requirements in a 5G
system.