Embodiments of this application provide a transmission direction configuration method, a device, and a system, and relate to the field of communications technologies. A specific solution is as follows: a terminal device receives first indication information from a network device, the first indication information is used to indicate a configuration of uplink and downlink transmission directions, the configuration is used to describe types, a number, and distribution of resource elements comprised in one period, the resource granularity comprises a time domain granularity, the time domain granularity comprises (OFDM) symbol, the types of the resource elements comprise at least one of an uplink resource element, a downlink resource element, or a switch resource element between the downlink resource element and the uplink resource element; and performs information transmission indicated by the first indication information, of the uplink and/or downlink transmission directions.