A method and an apparatus for carrying identification information are disclosed, to extend a quantity of bit positions that can represent identification information. The method includes determining, by a base station, bit locations that can be used to carry identification information in to-be-coded bits, where the bit locations that can be used to carry the identification information include locations of fixed bits, the identification information is used to identify a terminal, and the fixed bits are used by the terminal to perform error correction in a decoding process, adding, by the base station, the identification information to the bit locations, and encoding, by the base station in a polar code encoding mode, the to-be-coded bits that carry the identification information, and sending an encoded polar code to the terminal.