Embodiments of this application provide a data transmission method, a network device, and a terminal device. The method includes: determining, by a network device, demodulation reference signal DMRS port groups, where a quantity of the DMRS port groups is greater than or equal to 2; and further, communicating, by the network device, data with a terminal device, where the data is corresponding to a transport block, the transport block is divided into at least one code block group CBG, and each of the at least one CBG is corresponding to one DMRS port group and is mapped to a transport layer corresponding to the one DMRS port group.