Abstract: Decision Support System have widely been applied in many territory from 1970' s. The theoretical research and relational technique have fast been developed at same time, such as construction study on the DSS,model libraries technique, and so on. One of the emphasis theory study on the DSS is the construction design of the knowledge (intelligence) , pattern expressed by knowledge, way got knowledge,rational tactics,and so on. In this paper we emphasize the reaserch and design for the knowedge base and its management system,and apply in decision on forest fire extinguishment. This system may be applied in agriculture, economy system, and so on .