According to the new version of Basel Accord issued by June 2004, its main purpose is to raise the bank's risk measurement methods and control techniques, so the new Basel Capital Accord has become the important credit risk management guidelines of the bank. In 2008, China issued the IRB guideline, and in 2009 issued a senior commercial bank capital measurement method validation guidelines, as the important basis of CBRC to audit the implementation of the IRB. However, there are two specific features of current China financial market, government and state-owned companies involved in operating difficulty companies, and thus makes the default number of companies is relatively rare. Besides, earnings manipulation events are happened frequently. The above situations will result in a significant reduction in the number of companies defaulting samples, thereby significantly reducing the probability of default of credit analysis, and capital requirements will drastically reduced . This study will focus on the following two topics, first, if the government provides implicit support to exclude the possibility of the conditions, the number of companies or default ratio will increase significantly, or if considering implicit default, the default number of companies will increase significantly. Second, a considerable number of defaulting companies will carry out accounting fraud. The scope of this study listing companies after 2008, the specification of the Basel definition of default to filter and define the so-called recessive defaulting company is distinguished what is as accounting fraud, or as management company for further integration analysis to the internal rating of the modeling process to provide overall suggestion proposal.