Abstract: This paper discusses the principles,ways and moves of using cluster analysis and fuzzy comprehensive judgment to evaluate geological environment quality and applies them to geological environment quality evaluation of Shaannxi Province.Based on the complicity and variety of geological environment of Shaanxi Province and the feature which is controlled by various factors,this paper divides the whole Shaanxi Province into 350 sample elements and selects groundwater resource,surface water resource,water quality,land resource,topography,landforms,lithologic characteristics,vegetation,climate,earthquake,landslip mud-rock flow,endemic disease,soil erosion,desertification,land subsidence,surface geofracture,salinization swamp etc. 15 variables as evaluation factors,uses Q cluster analysis to divide the whole Shaanxi Province into 37 distribution areas of the geological environment quality,and classifies them into 7 grades of geological environment quality by using fuzzy comprehensive judgement,it reflects the macro distribution feature of the geological environmetn quality of Shaanxi Province objectively.The result is correct and reliable.