Optical components of large sized aspheric surface have gained significant importance and in?dispensability because of their desirable properties. However, efficient and economical manufacturing tech?niques are still critical problems to meet the demand for precision and quantity. Traditionally 2-axis NC ma?chine was used to manufacture axisymmetric aspheric surface. If a code disc offering accurate readings of the rotation angle is installed on the spindle, non-axisymmetric aspheric surfaces can be processed on it by em?ploying a diamond wheel. The corresponding geometric models for two kind of aspheric surfaces were pre-sented based on curvature analysis. By computer simulation it is verified that the machining approach can be made simple and reliable. According to geometric models the production efficiency can be improved and the equipment input can be reduced so that 3-D machining can be achieved by reforming a 2-axis machine.