The traditional expert method (5C elements) gaved its advantage and disadvantage is introduced and put forward to modifying expert method.Useing strategic tree help making policy,used judgment matrix seek element weight,modified shortcoming of traditional expert method and inherited its good point.Moifying expert method has a good perspective in present business bank credit particularly in a huge sum of credit.On the other hand Chinese business bank presently doesn't have the condition of using mathematic model estimate credit risk.So modifying expert method has a good perspective and actual meaning in Chinese business bank credit.