Embodiments of the present invention provide an uplink control information sending method, an uplink control information receiving method, an apparatus, and a system. The method includes: receiving, by a terminal device, channel indication information from an access network device on a physical control channel; determining the channel resource set that is of N channel resource sets and that matches a type or a size of the UCI as a first channel resource set; determining a channel resource that is in the first channel resource set and that is indicated by the channel indication information; and sending uplink control information UCI to the access network device on the channel resource. A quantity of bits that need to be added to the channel indication information in the embodiments of the present invention is less than that in the prior art.