Encoding and Decoding Methods and Devices, and System

An encoding method includes: obtaining a generator matrix for encoding, where the generator matrix is determined based on a target parity-check matrix of a Hamming code for encoding, the target parity-check matrix is based on a target function for decoding, the target function is used to determine a not-all-zero row vector extended based on the target parity-check matrix, and the target function is one of a predetermined function set; encoding information bits using the generator matrix to obtain an encoded data stream; and sending the encoded data stream.