Embodiments of this application disclose a polar coding method, apparatus, and device, so as to reduce storage overheads of a system. A sequence for polar coding is obtained based on a length M of a target polar code, wherein the sequence comprises L sequence numbers, ordering of the L sequence numbers in the sequence is the same as ordering of the L sequence numbers in a maximum mother code sequence, wherein the maximum mother code sequence is obtained by sorting N sequence numbers of N polarized channels in ascending order or descending order of reliability metrics, wherein L and N are integer power of 2, M is smaller than or equal to L, L is smaller than or equal to N.