Abstract: The uncertainty of resource have restricted breakthrough of Probable Geological Study from determine the nature to quantitative.The author,from the existence of resource to the use of resource,has analysed the influencing factor that measures recoverable reserves from resource,it is the Adjustable Coefficient of Extractable Reserve to sum up the Potential index of resources(A),creaibility index(B)and Exploitative index(C)combined action,K= A·B.C.①potential index depend on geological background,include regional metallogeny(A₁),geopnysical and geocnemical anomaly(A₂),and mine melt strength and continuously level(A₃);②Credibility index dep on type of detailed exploration(B₁)and control level(B₂);③Exploitative index depend on market the change of supply and demand(C₁),deposit tax store condition(C₂);The ore performance of processing technique(C₃);economic environmental and economic policy(C4).Paper uses the Adjustable Coefficient of Extractable Reserve finally,measures the resource of Lengshuibeigou mining area that resource investigates new discovery to adjust for Probable Extractable Reserve.