Embodiments of this application provide a downlink control information transmission method in which after receiving one piece of downlink control information (DCI), the terminal device learns whether blind detection of DCI needs to be continued. The method includes: A terminal device receives first DCI, where the first DCI includes first indication information, and the first indication information is used to indicate a first antenna port. The terminal device determines, based on the first antenna port and antenna port configuration information, whether second DCI exists. The configuration information may include an index of a CDM group to which each of a plurality of antenna ports belongs and a maximum quantity of CDM groups that is supported by the terminal device. Alternatively the configuration information may include one or more antenna port groups, and each of the one or more antenna port groups includes one or more antenna ports.