A communication method and a communications device, so that both a location and a length of information carried in a data packet header are flexible and variable, the length does not need to be fixed, and the location does not need to be specified. Compared with a conventional protocol, the communication method has stronger flexibility and higher scalability. The method includes: obtaining, by a first device, a data packet, where the data packet includes a first packet header, the first packet header includes first indication information and a value of first packet header information, the first indication information is used to indicate a location of the value of the first packet header information, and the first packet header information is device identification information; and processing, by the first device, the data packet.