In the application of CAD and GIS, the calculated quantity and complicacy of intersection between lines are very large; there have been a few methods to decrease the quantity of calculation,however, the intersection between line segments was still the traditional method. Our study established a method called“Local space transform”, can simplify the procession of intersection between line segments,improve the efficiency and decrease the complicacy. It proved in our experiment that more study is needed to improve the method.