This application provides an LDPC rate matching method and a communication apparatus. During retransmission, a transmit end repeatedly sends information bits of an LDPC codeword based on an order of repetition priorities of the information bits in rate matching, so that a performance gain of a receive end can be obtained. The order of repetition priorities of information bits is determined based on sensitivity of LDPC codewords. Therefore, in the order of repetition priorities, an information bit with higher sensitivity has a lower repetition priority, and an information bit with lower sensitivity has a higher repetition priority. Therefore, when the transmit end repeats the information bits of the LDPC codeword, an information bit with lower sensitivity is repeated first, so that decoding performance of the receive end can be improved.