This application provides a data transmission method and apparatus. The method performed by a network node includes: receiving an uplink data transmission request sent by a terminal, where the uplink data transmission request is used to request to allocate an uplink transmission resource; allocating an uplink transmission resource of a first subframe according to the uplink data transmission request, where the first subframe is an uplink subframe or a downlink subframe; sending scheduling control information to the terminal, where the scheduling control information is used to instruct the terminal to send data on the uplink transmission resource of the first subframe; and if the first subframe is a downlink subframe, stopping sending data in the first subframe, and receiving data on the uplink transmission resource of the first subframe.