Abstract: A new method of mesh-autodivision for space of electronic optical system is presented in this paper. And basing it, a program of "auto-adapting mesh-division for boundary of electronic optical system" is developed. With this program, the mesh-autodivision with small mesh pitch and the parameters of each mesh point for the close area of electronic optical system with arbitrary boundary can be achieved. Thus, the data-in of the system boundary and the modification of the boundary outline and the mesh pitch can be simplified and the designing of electronic optical system can be rapidly completed.