A method for determining a HARQ-ACK feedback time, a method for indicating a HARQ-ACK feedback time, a terminal device, and a network device are provided. The method includes: receiving a downlink control signaling, wherein the downlink control signaling carries a HARQ-ACK feedback time parameter, and the downlink control signaling is used to activate a downlink semi-persistent scheduling configuration; receiving semi-persistent scheduling data for downlink transmission on a first time-domain resource; and determining the HARQ-ACK feedback time of the semi-persistent scheduling data for the downlink transmission, based on the HARQ-ACK feedback time parameter and the first time-domain resource.