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, wherein the N polar channels respectively correspond to N rows of an encoding matrix of a polar code, 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 the polar code, N is a positive integer power of 2, and K≤N; selecting sequence numbers of K polar channels from the first sequence in descending order of the reliability; and mapping the to-be-encoded bits onto the K polar channels, and performing polar code encoding on the to-be-encoded bits, the method being characterized in that: reliability of an i th polar channel in the N polar channels meets a third reliability computation formula; and the third reliability computation formula is: W i = ∑ j = 0 n − 1 B j × ∑ ξ ∈ Ξ C ξ β 1 4 ξ j, wherein 1≤i≤N; W i is the reliability of the i th polar channel; n=Log 2 N; a binary representation of i-1 is given by B n -1 B n -2...B 1 B 0; B j is a value of a j th bit of a binary representation of a channel sequence number i, wherein B j ∈{0,1}; Ξ is a set of orders ξ comprised in the third reliability computation formula, wherein Ξ = {0,1} or Ξ = {0,1,2}; C(ξ) is a function of ξ, and represents a weight value of each order term, wherein ξ is an order comprised in Ξ, and C ξ = 1 4 ξ; and β is a constant greater than 1. obtaining a first sequence used to encode K to-be-encoded bits, wherein the first sequence comprises sequence numbers of N polar channels, wherein the N polar channels respectively correspond to N rows of an encoding matrix of a polar code, 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 the polar code, N is a positive integer power of 2, and K≤N; selecting sequence numbers of K polar channels from the first sequence in descending order of the reliability; and mapping the to-be-encoded bits onto the K polar channels, and performing polar code encoding on the to-be-encoded bits, the method being characterized in that: reliability of an i th polar channel in the N polar channels meets a third reliability computation formula; and the third reliability computation formula is: W i = ∑ j = 0 n − 1 B j × ∑ ξ ∈ Ξ C ξ β 1 4 ξ j, wherein 1≤i≤N; W i is the reliability of the i th polar channel; n=Log 2 N; a binary representation of i-1 is given by B n -1 B n -2...B 1 B 0; B j is a value of a j th bit of a binary representation of a channel sequence number i, wherein B j ∈{0,1}; Ξ is a set of orders ξ comprised in the third reliability computation formula, wherein Ξ = {0,1} or Ξ = {0,1,2}; C(ξ) is a function of ξ, and represents a weight value of each order term, wherein ξ is an order comprised in Ξ, and C ξ = 1 4 ξ; and β is a constant greater than 1. reliability of an i th polar channel in the N polar channels meets a third reliability computation formula; and the third reliability computation formula is: W i = ∑ j = 0 n − 1 B j × ∑ ξ ∈ Ξ C ξ β 1 4 ξ j, wherein 1≤i≤N; W i is the reliability of the i th polar channel; n=Log 2 N; a binary representation of i-1 is given by B n -1 B n -2...B 1 B 0; B j is a value of a j th bit of a binary representation of a channel sequence number i, wherein B j ∈{0,1}; Ξ is a set of orders ξ comprised in the third reliability computation formula, wherein Ξ = {0,1} or Ξ = {0,1,2}; C(ξ) is a function of ξ, and represents a weight value of each order term, wherein ξ is an order comprised in Ξ, and C ξ = 1 4 ξ; and β is a constant greater than 1.