Abstract: The demarcation of nature reserves is an important work to ensure the effective management of nature reserves, and lays a solid foundation for finding out the area and scope of nature reserves. Starting from the actual situation of demarcation work and on the basis of summarizing the existing problems of data processing in demarcation work, this paper uses c# program language and ArcGIS plug-in technology to develop demarcation points, automatic numbering tool of boundary points, generation tool of demarcation point registration table,compilation tool of boundary trend description, automatic measurement tool of boundary point elevation, etc..The developed tool can generate demarcation results in batch, and can be effectively used in the demarcation data processing of multiple natural reserves, which improves the work efficiency of demarcation