A transmission method, applied to a network device and comprising: performing polar encoding on a bit sequence, to obtain an encoded sequence, wherein the bit sequence comprises control information and a cyclic redundancy check CRC sequence; fragmenting the encoded sequence, to obtain n encoded subsequences, wherein n is an integer, and n>1; scrambling the n encoded subsequences by using n scrambling sequences respectively, to obtain n scrambled sequences; and performing modulation and mapping operations on the n scrambled sequences, and sending the n scrambled sequences after the modulation and mapping, wherein each of the n encoded subsequences has a length of N bit and is rearranged in an even-numbered vector of the subsequence concatenated by an odd-numbered vector of the subsequence, wherein the scrambling the n encoded subsequences by using n scrambling sequences respectively specifically comprises: performing an exclusive-OR operation on the concatenated even-numbered vector and odd-numbered vector of each of the n encoded subsequences with the n scrambling sequences respectively, wherein the scrambling sequences each also have a length of N bits, wherein the odd-number vector of one of the n encoded subsequences comprises bits in the one of the n encoded subsequences whose indices are odd-number, and the even-number vector of one of the n encoded subsequences comprises bits in the one of the n encoded subsequences whose indices are even-number, and wherein the n scrambling sequences carry ⌈ log 2 n ⌉ -bit information. performing polar encoding on a bit sequence, to obtain an encoded sequence, wherein the bit sequence comprises control information and a cyclic redundancy check CRC sequence; fragmenting the encoded sequence, to obtain n encoded subsequences, wherein n is an integer, and n>1; scrambling the n encoded subsequences by using n scrambling sequences respectively, to obtain n scrambled sequences; and performing modulation and mapping operations on the n scrambled sequences, and sending the n scrambled sequences after the modulation and mapping, wherein each of the n encoded subsequences has a length of N bit and is rearranged in an even-numbered vector of the subsequence concatenated by an odd-numbered vector of the subsequence, wherein the scrambling the n encoded subsequences by using n scrambling sequences respectively specifically comprises: performing an exclusive-OR operation on the concatenated even-numbered vector and odd-numbered vector of each of the n encoded subsequences with the n scrambling sequences respectively, wherein the scrambling sequences each also have a length of N bits, wherein the odd-number vector of one of the n encoded subsequences comprises bits in the one of the n encoded subsequences whose indices are odd-number, and the even-number vector of one of the n encoded subsequences comprises bits in the one of the n encoded subsequences whose indices are even-number, and wherein the n scrambling sequences carry ⌈ log 2 n ⌉ -bit information. performing an exclusive-OR operation on the concatenated even-numbered vector and odd-numbered vector of each of the n encoded subsequences with the n scrambling sequences respectively, wherein the scrambling sequences each also have a length of N bits, wherein the odd-number vector of one of the n encoded subsequences comprises bits in the one of the n encoded subsequences whose indices are odd-number, and the even-number vector of one of the n encoded subsequences comprises bits in the one of the n encoded subsequences whose indices are even-number, and wherein the n scrambling sequences carry ⌈ log 2 n ⌉ -bit information.