An encoding method, an encoding apparatus, a decoding method, and a decoding apparatus are provided. The encoding method includes: determining a size of a shift matrix based on a length of an information sequence and a length of an identifier sequence; constructing a check matrix based on the size of the shift matrix and a base matrix; and performing low-density parity-check LDPC encoding on the information sequence and the identifier sequence based on the check matrix. The identifier sequence is a non-all-zero sequence. Because the encoded codeword includes information of the identifier sequence, a receive device can identify whether information corresponding to the encoded codeword is addressed to the receive device, thereby improving information processing efficiency in the transmission.