A method includes: receiving, by the terminal device, at least one piece of downlink data and DCI corresponding to the at least one piece of downlink data, where the DCI includes first indication information, and the first indication information indicates a target transmission time interval (TTI) for transmitting HARQ-ACK feedback information corresponding to the at least one piece of downlink data; generating, by the terminal device based on second indication information, HARQ-ACK feedback information that needs to be fed back in the target TTI, where the second indication information indicates the number of bits of the HARQ-ACK that needs to be fed back in the target TTI; and sending, by the terminal device, the generated HARQ-ACK feedback information to the network device in the target TTI.