This application relates to the field of wireless communications technologies, and discloses a polar code encoding method and apparatus, to improve accuracy of reliability calculation and ordering for polarized channels. The method includes: obtaining a first sequence used to encode K to-be-encoded bits, where the first sequence includes sequence numbers of N polarized channels, the sequence numbers of the N polarized channels are arranged in the first sequence based on reliability of the N polarized channels, K is a positive integer, N is a mother code length of a polar code, N is a positive integer power of 2, and K≤N; selecting sequence numbers of K polarized channels from the first sequence in descending order of reliability; and placing the to-be-encoded bits based on the selected sequence numbers of the K polarized channels, and performing polar code encoding on the to-be-encoded bits.