An interleaving method and apparatus are provided, to reduce complexity of implementation processes of polar code interleaving and rate matching. The method includes: obtaining encoded bits after polar code encoding, and sorting the encoded bits based on a priority order of performing a rate matching operation, to obtain a first bit sequence. The first bit sequence includes j subsequences, and j is a positive integer. The method further includes writing the first bit sequence into an interleaver of i rows and j columns. Bits in a column in the interleaver include one of the j subsequences; and reading out bits from the interleaver column by column, until M bits are read. At least two adjacent columns have opposite readout directions, and M is a target code length.