Cyclic mapping method and device

A cyclic mapping method and device. The method comprises: classifying bit positions in a cyclic buffer according to modulation parameters; and sequentially mapping channel-coded system bits and check bits to the bit positions in the cyclic buffer according to obtained classification information of the bit positions. Bit positions in a cyclic buffer are classified according to different modulation modes; and system bits and check bits are sequentially mapped to the bit positions in the cyclic buffer according to obtained classification information of the bit positions, and accordingly, system bits are prevented from being placed on front ends of the cyclic buffer in a centralized manner, the probability that the system bits are allocated to highly reliable bit positions is increased, the bit error rate of a system is reduced, and the reliability of the system is improved.