Embodiments of this application disclose encoding and decoding methods and apparatus related to the communications. One of the methods includes: obtaining, based on polar code rate matching, a subchannel corresponding to a punctured bit or a shortened bit; determine subchannels corresponding to an information bit and a check frozen bit that are different from the subchannel corresponding to the punctured bit or the shortened bit; determining that a subchannel corresponding to a frozen bit that is different from the subchannels corresponding to the information bit and the check frozen bit and the subchannel corresponding to the punctured bit or the shortened bit; performing, according to the subchannels corresponding to the information bit and the check frozen bit and the subchannel corresponding to the frozen bit, parity check encoding and polar encoding based on the information bit to obtain encoded information; and sending the encoded information.