城市地质环境质量评价是城市规划和建设的重要参考依据。西安是一座历史名城，又是陕西的省会城市，它在西部大开发过程中起着举足轻重的作用。对西安城市地质环境质量进行评价并对其地质环境问题进行深入研究，对促进西部开发和城市化健康发展，建立良好的城市地质环境具有重要的现实意义。 本文综合分析了西安市主城区地质环境的主要影响因素，在总结前人研究成果的基础上，结合国家标准，根据西安城市地质环境问题的特点，选取了地形坡度、地裂缝、地面沉降、黄土湿陷性、断裂、地基承载力和人类工程活动7个指标作为评价因子，建立了西安市地质环境质量评价指标体系和分级标准。在此基础上，按地貌单元划分评价单元，用MAPGIS建立了西安市城区空间图形数据库，并进行了查询分析、叠加分析、数字高程模型分析等空间分析，获得了各区定量评价指标值。采用专家打分法对定性评价指标进行量化赋值，并用灰色关联法计算各指标权重，最后用模糊综合评判方法进行了评价。据此，参照国家标准并结合西安市城区地质环境的特点，把西安市城区地质环境质量划分为优、良、中、差四个质量等级，并根据评价结果提出了合理的防治措施和保护建议。 经与实际对比，表明该评价模型合理、可行，具有较强实用性。对全国类似城市环境质量评价具有一定参考价值。

Urban geo-environment assessment is most important part of urban planning and urban geological disaster prevention and control planning. Xi'an is a historic city and is also the capital city of Shaanxi，which plays a vital role in the course of western development. It has an important practical significance that evaluating the quality of geological environment of Xi'an and depth-studying its geological problems， in promoting the western development and the healthy development of urbanization， and setting up a good geological environment. The thesis has analyzed main factors influencing city region geo-environment synthetically. On the basis of summarizing predecessors’ experience and the characteristic of geo-environment problems of the Xi’an， it selected the terrain slope， ground fissures， land subsidence， loess collapsibility， fracture， the foundation bearing capacity and human engineering activities 7 indexes for evaluating the target. Combined with national standards， a geo-environmental quality assessment index system and grading standards of Xi'an are determined，. Based on the development platform of MAPGIS， the Spactial graphics database of Xi'an is established， and the thesis took query analysis， overlay analysis，digital elevation model analysis of spatial analysis function. River geomorphological zoning was as the evaluation unit， the precise value of quantitative indicators of the various districts is got by analysising. For the qualitative indicators， the expert scoring method is mainly used to quantify its indicators. For quantitative indicators， membership function values is used， according to the evaluation of grading criteria. The weights is calculated by using gray relational method， and finally the fuzzy comprehensive evaluation model is used to evaluate. The quality of geological environment in Xi'an was classified into best good,moderate， worst. And a review has been done according to their respective characteristics and the thesid put forward a reasonable preventive measures and protection recommendations. So,it further indicates that the system is reasonably practicable,with strong practicality.