Abstract: The aim of this paper is to improve a proved method of the channel coding theorem that is most important in Information Theory.It is found out that the theory that the threshold value decoding is possibly multivalent does not conform to the fact and may result in having to define two types of errors.The proved process becomes redundant and complex.Therefore,the threshold value decoding is reworked in this paper,and the error probability is improved,solving those problems above.Decoding becomes simple.