Encoding and decoding method of low density parity check code

A decoding method of low density parity check code, adapted to an encoded data which is associated with a primary low density parity check matrix. The primary low density parity check matrix includes a plurality of local low density parity check matrices and a global low density parity check matrix. The method includes the steps of: (A) a encoding device encodes the encoded data according to the local low density parity check matrices of the primary low density parity check matrix; (B) the encoding device determines if the encoded data can be completely decoded; and (C) When the encoding device determines that the encoded data can't be completely decoded, the encoded data is decoded according to the global low density parity check matrix of the primary low density parity check matrix.