A method includes determining, based on a length of to-be-encoded information bits and a code rate, a code length N after encoding; determining, based on N, a minimum segment code length and a maximum segment code length, a reserved segment quantity of each type of segments in segments of b−a+1 types of segment code lengths and a reserved code length corresponding to N, where the minimum segment code length is 2{circumflex over ( )}a, and the maximum segment code length is 2{circumflex over ( )}b; determining a segment quantity of each type of segments based on N, the reserved code length, a segment code length of each type of segments, and the reserved segment quantity, where N corresponds to S segments, and a segment code length of an ith segment in the S segments is greater than or equal to a segment code length of an (i+1)th segment in the S segments.