Embodiments can provide a coding method, a coding apparatus, and a communications apparatus. The method includes: determining N to-be-coded bits, where N is a positive integer; obtaining a first sequence that includes N polar channel sequence numbers; determining a location of an information bit in the N to-be-coded bits based on the first sequence; and performing polar coding on the N to-be-coded bits to obtain coded bits. The location of the information bit in the to-be-coded bits is determined based on the obtained first sequence that includes N polar channel sequence numbers, so that performance of a polar code can be improved.