This application provides a data transmission method, a network device, and a terminal device. The method includes: generating, by the network device, first information, where a value of a bit included in the first information is used to indicate a demodulation reference symbol (DMRS) port combination in a second set, each DMRS port combination in the second set belongs to a first set, the first set includes a plurality of DMRS port combinations, the DMRS port combination includes at least one DMRS port, and a quantity of DMRS port combinations included in the second set is less than a quantity of DMRS port combinations included in the first set; and sending, by the network device, the first information to the terminal device. According to embodiments of this application, signaling overheads can be reduced.