Abstract: This paper introduces the technico-economic characteristics of the "CAD system of blanking die design" developed by Luoyang Institute of Technobgy, and describes the application of the node method in the treatments of graph inputting and dimension tolerance notes. The emphasis is on explaining the mathematical method to determine unknown nodes when the node method is used to input graphs. In addition, this paper describes the establishment process of function expression under AUTOCAD software package condition when the node method is used to input dimension tolerance.