SMEs(small and medium enterprises) can not develop without the support of banks. The unreasonable evaluation of SMEs which is from bands directly impeded SMEs’ financing. Banks’ SMEs credit evaluation system is imperfect, evaluation methods are too general. A method, visual and easy to calculate, structural stability and high precision, is named correction of genetic Judgment Matrix AHP (AGA-CAHP), combined with expert method can solve the problem, then evaluate the credit of SMEs.