Embodiments of the present invention provide a polar code hybrid automatic repeat request method and an apparatus. The method includes: obtaining, by a communications device, a bit sequence of retransmission information, where the bit sequence of the retransmission information includes K retransmission information bits determined from a bit sequence of first transmission information, the bit sequence of the first transmission information includes N first transmission information bits, N is a positive integer, and K is a positive integer not greater than N; performing, by the communications device, polar code encoding on the bit sequence of the retransmission information, to obtain an encoded retransmission bit sequence; and sending, by the communications device, the encoded retransmission bit sequence to another communications device.