Based on the characteristics of small and micro businesses, we combine the theory with commercial bank practice to sort out and analyze the factors influencing the credit situation of small and micro enterprises. The index of small micro enterprise credit evaluation is constructed, which we add the factor of cash flow information. Based on a sample of actual borrowers from a large China commercial bank, the results reveal that LSSVM outperform the other techniques with the measure of ROC. In addition, this paper proves that cash flow index plays an important role in the credit evaluation of the small and micro enterprises through the empirical test. This study provides theoretical support and practical experience for Chinas commercial bank screening small and micro businesses credit evaluation index and building credit evaluation model.