CT This paper presents a rapid detecting method to tell the external contours from internal ones, and adopt an aid measure of adding 'black points" . These two methods result in obtaining the high reliability of pattern separation. For the recognizing hand-written symbols, we propose an extracting feature method projecting four sidehands and bring it in the decision tree. It can lead to increasing the recognition rate and speed obviously. After the system understands the topologic relationship, it can still link with ORCAD which is an international current CAD software.