This application provides a precoding processing method and a communication apparatus, and relates to the field of communication technologies. A sending apparatus may determine precoding information, where the precoding information may include one or more of the following: a precoding codebook, a power of a precoding port, a power of a precoding data stream, and a correspondence between the precoding port and the precoding data stream, where one or more precoding ports correspond to one precoding data stream. The sending apparatus transmits precoding information to a receiving apparatus, so that the receiving apparatus can transmit downlink data with reference to the precoding information. In this application, the sending apparatus feeds back more types of precoding information, so that the receiving device obtains more reference information when transmitting the downlink data. In addition, each precoding port corresponds to one precoding data stream, so that a feature of a low peak to average power ratio PAPR of the precoding codebook can be ensured.