Abstract: This paper mainly studies the LDPC code high quality communication channel coding technology.In the traditional BP algorithm,LLR BP decoding algorithm based on the minimum,and algorithm in the test node update process exist the problem of large external information,this paper proposes an improved LDPC decoding algorithm. Algorithm based on BP algorithm is scaling,to make it more close to the actual value,the simulation results show that,the improved algorithm improves the LDPC code and the decoding algorithm for minimum error correction performance.