Abstract: To readjust the industrial structure and layout,resources must be integrated and the regional advantages of hilly areas must be exploited.The basic control nets,i.e. the D grade GPS net and the national third grade level net,can be developed according to the overall planning.That project can improve the construction of the basic control network in the hilly areas of China,which is significant to the hilly area surveying and mapping.The related technology outline,setting program,surveying method in field,data processing,and accuracy analysis are introduced.

Key words: third grade level net, hilly area, net setting