This application provides an information transmission method and a communications apparatus. The method includes: receiving downlink control information DCI, where the DCI includes indication information, the indication information indicates at least one demodulation reference signal DMRS antenna port group and layer information of downlink data, the at least one DMRS antenna port group is one or more of a plurality of DMRS antenna port groups, and DMRS antenna ports in a same DMRS antenna port group satisfy a quasi co-location QCL relationship; and determining, based on the indication information, a DMRS antenna port occupied by the downlink data. According to embodiments of this application, a DMRS antenna port can be indicated when DMRS antenna ports are grouped.