The present invention discloses a method, an apparatus and a system for low-density parity-check (LDPC) coding and decoding. The coding method includes the following steps: constructing each layer of a check matrix of a layered LDPC code used as an error correcting code; when data is initially sent by a data transmitting terminal, performing first-layer-coding of the data to be sent by using the first layer of a check matrix of the LDPC code, sending the first-layer-coded data; when data for (n−1)th retransmission is sent by the data transmitting terminal, performing nth-layer-coding of the data by using the nth layer of a check matrix of the LDPC code, sending the nth-layer-coded data, wherein n is an integer no less than 2. It is possible to reduce the system overhead, decrease the decoding delay, and improve the decoding performance by using the technical solution of the present invention which is also adapted to high-speed data services.