Embodiments of this application provide an information processing method and a coding apparatus. An information bit sequence includes a K-bit information block. The information bit sequence is to be processed into an encoded bit sequence with a target code length M, M>1024. For a given code rate R, when the length K of the information block is greater than a preset threshold, the information bit sequence is segmented into two or more segments. Each segment is polar encoded into an encoded subsequence. The encoded subsequence has a length that equals to a mother code length Ni, and i=1, 2, . . . , p. Each of the p encoded subsequences is rate matched to obtain a rate-matched encoded subsequence. A rate-matched encoded subsequence i of the p rate-matched encoded subsequences has a code length Mi. The p rate-matched encoded subsequences are concatenated into an encoded bit sequence which has a code length M.