北祁连成矿带是青海省内重要的铜铅锌金铁等多金属成矿带，矿床类型繁多，地质特征复杂，具有一定的找矿潜力。但由于整个北祁连地区面积较大，所涉及图幅过多，导致取得的大量化探基础资料没有进行系统地分析研究，而采用传统化探成图方法无法全面地反映真实的异常程度，影响找矿效果，这极大地制约了进一步找矿成果的取得和勘查后备基地的优选。基于以上问题，利用衬值法对青海省北祁连地区大面积区域化探数据进行了处理成图，并将处理后的数据与已有矿床和真值原始数据进行对比验证，实际效果十分理想，克服了常规化探成图方法带来的困难，可为后期大面积区域化探数据的处理工作提供参考。

The North Qilian metallogenic belt in Qinghai Province is an important copper，lead，zinc，gold and iron polymetallic metallogenic belt with various deposit types，complex geological features and some prospecting potential. However，due to the large area of the entire North Qilian area and too much mappable unit involved，a large number of obtained basic geochemical data is without systematic analysis.While，the traditional geochemical mapping methods can not completely reflect the true degree of abnormality，and it can affects the prospecting effect，which greatly restrict the further prospecting and optimization of exploration reserve base.Based on the issues mentioned above，the abnormal contrast method is employed for geochemical data processing into map in the North Qilian area of Qinghai Province. Additionally，the processed data is compared validation with existing deposits and the true value of the raw data.The actual results are quite satisfactory and we have overcomed the difficulties of conventional geochemical mapping，which can provide a reference for post-processing of large regional geochemical data.