Abstract: On the basis of describing the reasoning processes of both the ordinary forward-chaining and graphapproach.the advantages of the graph approach in the aspects of reasoning efficiency,realizing inexact andnonmonotonic reasoning are analyzed in this paper.In order to make this approach be suitable for the problems inwhich "pattern variable" exists,an improved graph inference approach—dynamic graph inference approach isproposed.An inference engine based on this approach is briefly introduced in the last part of this paper.