The present disclosure relates to polar decoding methods and apparatus. One example method includes obtaining a polar code sequence, determining at least one first information bit length corresponding to a code length of the polar code sequence, and decoding the polar code sequence based on blind detection by using the code length and the at least one first information bit length. The at least one first information bit length is a part of a preset information bit length set corresponding to the code length. A remaining part of the preset information bit length set is at least one second information bit length. The at least one second information bit length is excluded from being used for the blind detection. Each second information bit length is less than one or more information bit lengths in the at least one first information bit length.