This application provides a control information sending method, including determining L pieces of control information from M pieces of control information based on a priority rule, where the M pieces of control information include M1 pieces of uplink control information and M2 pieces of sidelink control information, types of M1 pieces of uplink control information include a hybrid automatic repeat request, a scheduling request, and channel state information, types of M2 pieces of sidelink control information include a sidelink hybrid automatic repeat request, a sidelink scheduling request, and sidelink channel state information, M is a positive integer greater than or equal to 2, M1 is an integer greater than or equal to 0, M2 is an integer greater than or equal to 1, and L is an integer greater than or equal to 0 and less than or equal to M, and sending the L pieces of control information.