A polar code encoding method, comprising: obtaining a first sequence used to encode K to-be-encoded bits, wherein the first sequence comprises sequence numbers of N polar channels, and the sequence numbers of the N polar channels are arranged in the first sequence based on reliability of the N polar channels, wherein K is a positive integer, N is a mother code length of a polar code, N=2 n, n is a positive integer, and K≤N; selecting sequence numbers of K polar channels from the first sequence in descending order of the reliability; 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; wherein the first sequence is a second sequence or a subset of a second sequence, the second sequence comprises sequence numbers of N max polar channels, and the sequence numbers of the N max polar channels are arranged in the second sequence based on reliability of the N max polar channels, wherein N max is a positive integer power of 2, and N max ≥N; characterized in that reliability of an i th polar channel in the second sequence is: W i = ∑ j = 0 n − 1 B j × β j + 0.169 × 0.8805 j − B 6 × 0.096 × 0.2432 + 0.2432 I j + B 9 × 0.038 × 0.8262 j or W i = ∑ j = 0 n − 1 B j × β j + 0.169 × 0.601 j − B 6 × 0.07694 × 0.0769 + 0.0769 I j wherein 0≤i≤N-1; W i is the reliability of the i th polar channel; i meets i = B n -1 B n -2... B 0, wherein B n -1 B n -2... B 1 B 0 is a binary representation of i; B j is a value of a j th bit in the binary representation of the channel sequence number i, wherein B j ∈{0,1}: β = 2 1 4. and I is an imaginary unit. obtaining a first sequence used to encode K to-be-encoded bits, wherein the first sequence comprises sequence numbers of N polar channels, and the sequence numbers of the N polar channels are arranged in the first sequence based on reliability of the N polar channels, wherein K is a positive integer, N is a mother code length of a polar code, N=2 n, n is a positive integer, and K≤N; selecting sequence numbers of K polar channels from the first sequence in descending order of the reliability; 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; wherein the first sequence is a second sequence or a subset of a second sequence, the second sequence comprises sequence numbers of N max polar channels, and the sequence numbers of the N max polar channels are arranged in the second sequence based on reliability of the N max polar channels, wherein N max is a positive integer power of 2, and N max ≥N; characterized in that reliability of an i th polar channel in the second sequence is: W i = ∑ j = 0 n − 1 B j × β j + 0.169 × 0.8805 j − B 6 × 0.096 × 0.2432 + 0.2432 I j + B 9 × 0.038 × 0.8262 j or W i = ∑ j = 0 n − 1 B j × β j + 0.169 × 0.601 j − B 6 × 0.07694 × 0.0769 + 0.0769 I j wherein 0≤i≤N-1; W i is the reliability of the i th polar channel; i meets i = B n -1 B n -2... B 0, wherein B n -1 B n -2... B 1 B 0 is a binary representation of i; B j is a value of a j th bit in the binary representation of the channel sequence number i, wherein B j ∈{0,1}: β = 2 1 4. and I is an imaginary unit.