A data processing method, comprising: saving, by a first communications device, a third encoded bit segment in a circular buffer of the first communications device, wherein the third encoded bit segment is a bit segment obtained by encoding a code block based on a low-density parity-check, LDPC, parity check matrix, the third encoded bit segment does not comprise a first to-be-punctured bit segment, the LDPC parity check matrix comprises a puncture column, and the first to-be-punctured bit segment comprises information bits corresponding to the puncture column; determining (S210, S510), by the first communications device, a first encoded bit segment having a length of N CB from the third encoded bit segment, wherein N CB is determined based on a size of the circular buffer of the first communications device and an information processing capability of a second communications device; and obtaining (S220, S520), by the first communications device, a second encoded bit segment from the first encoded bit segment; wherein the information processing capability of the second communications device comprises a size N CB, max of a maximum coded block supported by a decoder of the second communications device and a size N IR of a soft information buffer of the second communications device, wherein N CB = min K W N CB, max ⌊ N IR C ⌋, C is a quantity of code blocks in a transport block of information transmitted by the first communications device to the second communications device, and K W is the size of the circular buffer of the first communications device; or the information processing capability of the second communications device comprises a size N CB, max of a maximum coded block supported by a decoder of the second communications device, wherein N CB = min( K W, N CB, max), and K W is the size of the circular buffer of the first communications device; wherein the obtaining (S220, S520), by the first communications device, a second encoded bit segment from the first encoded bit segment comprises: determining, by the first communications device, a first starting position in the first encoded bit segment based on a sent redundancy version; and obtaining, by the first communications device as the second encoded bit segment, an encoded bit segment having a length of n from the first starting position in the first encoded bit segment, wherein n is a positive integer. saving, by a first communications device, a third encoded bit segment in a circular buffer of the first communications device, wherein the third encoded bit segment is a bit segment obtained by encoding a code block based on a low-density parity-check, LDPC, parity check matrix, the third encoded bit segment does not comprise a first to-be-punctured bit segment, the LDPC parity check matrix comprises a puncture column, and the first to-be-punctured bit segment comprises information bits corresponding to the puncture column; determining (S210, S510), by the first communications device, a first encoded bit segment having a length of N CB from the third encoded bit segment, wherein N CB is determined based on a size of the circular buffer of the first communications device and an information processing capability of a second communications device; and obtaining (S220, S520), by the first communications device, a second encoded bit segment from the first encoded bit segment; wherein the information processing capability of the second communications device comprises a size N CB, max of a maximum coded block supported by a decoder of the second communications device and a size N IR of a soft information buffer of the second communications device, wherein N CB = min K W N CB, max ⌊ N IR C ⌋, C is a quantity of code blocks in a transport block of information transmitted by the first communications device to the second communications device, and K W is the size of the circular buffer of the first communications device; or the information processing capability of the second communications device comprises a size N CB, max of a maximum coded block supported by a decoder of the second communications device, wherein N CB = min( K W, N CB, max), and K W is the size of the circular buffer of the first communications device; wherein the obtaining (S220, S520), by the first communications device, a second encoded bit segment from the first encoded bit segment comprises: determining, by the first communications device, a first starting position in the first encoded bit segment based on a sent redundancy version; and obtaining, by the first communications device as the second encoded bit segment, an encoded bit segment having a length of n from the first starting position in the first encoded bit segment, wherein n is a positive integer. determining, by the first communications device, a first starting position in the first encoded bit segment based on a sent redundancy version; and obtaining, by the first communications device as the second encoded bit segment, an encoded bit segment having a length of n from the first starting position in the first encoded bit segment, wherein n is a positive integer.