In a method for receiving downlink control information, a terminal device sends first data to a network device in a first time unit, where the first data is uplink transmission without uplink grant signaling. The terminal device further receives downlink control information in a second time unit, where the downlink control information includes resource allocation information and a first radio network temporary identifier (RNTI). The terminal device determines, based on the first RNTI, that the downlink control information is for the uplink transmission without uplink grant signaling; and retransmits a part or all of the first data on a resource corresponding to the resource allocation information, or sends second data on a resource corresponding to the resource allocation information, where the second data and the first data are data of a same HARQ process.