A data transmission method and an apparatus are provided. The method includes: A terminal device receives DCI from a network device, where the DCI is used to schedule downlink data and indicate a modulation scheme of the downlink data, the modulation scheme of the downlink data is a first modulation scheme or QPSK, and a modulation order corresponding to the first modulation scheme is greater than 2; and the terminal device receives the downlink data based on the modulation scheme. Based on the foregoing procedure, the network device indicates the modulation scheme of the downlink data by using the DCI, so that the terminal device receives the downlink data based on the modulation scheme indicated by the DCI. In this way, scheduling based on higher order modulation indicated by using the DCI is implemented.