引入PEG（Progressive-edge-growth）算法来构造适合线性时间编码的LDPC校验矩阵，译码时采用简化最小和Min-Sum译码算法实现简化译码．仿真结果表明，该方法能够构造适合LDPC码的线性时间编码的下三角校验矩阵日，并且用此方法构造的LDPC码性能非常接近原来PEG算法构造的LDPC码．同时通过采用最小和Min-Sum算法降低译码复杂度．,The introduction of PEG (Progressive-edge-growth) algorithm to construct suitable for linear time encoding of LDPC check matrix, decoding simplified when the smallest and the Min-Sum decoding algorithm decoding simplified. Simulation results show that this method can construct LDPC codes suitable for linear time encoding on lower triangular calibration matrix, and constructed using this method the performance of LDPC code is very close to the original PEG algorithm constructed LDPC codes. At the same time through the use of the smallest and the Min-Sum decoding algorithm to reduce complexity.