A data transmission method and apparatus are provided. The method includes: A terminal device sends a message 1 to a first network device, where the message 1 includes a random access preamble. The terminal device receives DCI and a message 2 scheduled by the DCI from the first network device, where the message 2 includes downlink data, the DCI and/or the message 2 include/includes first information, and the first information is used to schedule ACK/NACK feedback information of the message 2. The terminal device sends the ACK/NACK feedback information to the first network device based on the first information. According to the foregoing method, the first information is used to schedule the ACK/NACK feedback information. Therefore, the terminal device may send the ACK/NACK feedback information of the message 2 to the first network device in an MT-EDT scenario and based on the first information included in the DCI and/or the message 2, to improve robustness of transmission of the downlink data in the message 2.