Xicheng lead-zinc mineral field is one of the domestic gigantic mineral fields at high degree. The area around Xicheng can still discover some worthy mineral fields in recent years. The authors analyzed the geology condition and the control factor at the base of the comprehensive research of the former results and the mineral bed of the forming mineral characteristics. Then, the authors analyzed the space relation inside contact of the mineral bed and touch each factor in data-base quickly and tried to fix the position of the mineral bed and estimate the mineral ore in prognosis under the weights of comprehensive evidence and the potential method according to the technique of GIS. At last, the authors put forward mineral prospect field of the third class according to a beneficial condition of the mineral field.