Soil erosion survey is one of the main tasks in the first national water resources survey.To obtain the field investigation unit data,substantive ground sampling need to be made,and a large number of base map for field investigation unit are required to assist field investigations.Then spatial analysis will be adopted to get various erosion factors by using the acquired data.Since China has a very vast area and erosion area,the number of field investigation unit base map is huge.The procedures of base map cartography,which involves amounts of data,are usually cumbersome and repetitive.Therefore,this paper studied the implementation of automated mapping on soil erosion sampling survey unit base maps by using C^# programming,Visual Studio 2008and ArcEngine component-based development.By programming,this study achieved automated mapping,as map clipping,calculation,classification,layout and printing could be done automatically.This study also elaborately described the functions and concept in automatic cartography in three sections:map clipping,map projection and map layout.