A method for sending indication information, comprising: determining, by a network device, hybrid automatic repeat request-acknowledgment, HARQ-ACK feedback indication information used to instruct a plurality of terminal devices to feed back, wherein the HARQ-ACK feedback indication information is used to indicate a transmission time interval commonly occupied by the plurality of terminal devices to feed back an HARQ-ACK and proprietary information about an HARQ-ACK fed back by individual terminal devices, and the proprietary information comprises a bit quantity of the HARQ-ACK that individual terminal devices needs to feed back, or the proprietary information comprises a bit quantity of the HARQ-ACK that individual terminal devices need to feed back and a channel resource used by each terminal device to feed back the HARQ-ACK; and sending, by the network device, the HARQ-ACK feedback indication information to the plurality of terminal devices; receiving, from at least one terminal device in the plurality of terminal devices, an HARQ-ACK based on the transmission time interval commonly occupied by the plurality of terminal devices to feed back the HARQ-ACK and the proprietary information about the HARQ-ACK fed back by the at least one terminal device in the HARQ-ACK feedback indication information; wherein the method further comprises: sending, by the network device to an N th terminal device of the plurality of terminal devices, location index information corresponding to the N th terminal device, wherein the location index information is used to indicate a location of a bit quantity of an HARQ-ACK fed back by the N th terminal device and a channel resource used to feed back the HARQ-ACK, in the HARQ-ACK feedback indication information, and N ranges from 1 to a quantity of the plurality of terminal devices. determining, by a network device, hybrid automatic repeat request-acknowledgment, HARQ-ACK feedback indication information used to instruct a plurality of terminal devices to feed back, wherein the HARQ-ACK feedback indication information is used to indicate a transmission time interval commonly occupied by the plurality of terminal devices to feed back an HARQ-ACK and proprietary information about an HARQ-ACK fed back by individual terminal devices, and the proprietary information comprises a bit quantity of the HARQ-ACK that individual terminal devices needs to feed back, or the proprietary information comprises a bit quantity of the HARQ-ACK that individual terminal devices need to feed back and a channel resource used by each terminal device to feed back the HARQ-ACK; and sending, by the network device, the HARQ-ACK feedback indication information to the plurality of terminal devices; receiving, from at least one terminal device in the plurality of terminal devices, an HARQ-ACK based on the transmission time interval commonly occupied by the plurality of terminal devices to feed back the HARQ-ACK and the proprietary information about the HARQ-ACK fed back by the at least one terminal device in the HARQ-ACK feedback indication information; wherein the method further comprises: sending, by the network device to an N th terminal device of the plurality of terminal devices, location index information corresponding to the N th terminal device, wherein the location index information is used to indicate a location of a bit quantity of an HARQ-ACK fed back by the N th terminal device and a channel resource used to feed back the HARQ-ACK, in the HARQ-ACK feedback indication information, and N ranges from 1 to a quantity of the plurality of terminal devices.