The relationship between lender and debtor is different from that of buyer and seller because of the asymmetric income and risk between the two. By setting up a game model of bank-enterprise credit relationship, this paper indicates that the primary reason of "market invalidation"and distribution invalidation caused from the distortion of capital price is the asymmetric information in credit markets. We also find that governmental policies are the most critical factor to solve the problem of asymmetric information in credit markets, besides the factors of standardization of the bank interior management and improvement of the enterprise management transparency.