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