A polar code coding method and apparatus are provided. The method includes: determining, based on a target code length corresponding to an information bit sequence, a first mother code length corresponding to the information bit sequence; and performing polar code coding on the information bit sequence based on the first mother code length and mapping relationship information, where the mapping relationship information includes a correspondence between a mother code length and at least one of the following: a transport block size, a construction work point, or a construction sequence. In the method provided in the embodiments of the present invention, polar code coding may be directly performed on the information bit sequence based on at least one of a first transport block size, a first construction work point, or a first construction sequence, so as to reduce coding overheads in a polar code coding process.