《机械制图》是工科院校一门技术基础课,它既有系统的理论性,又有很强的实践性。主要是培养学生的看图和画图能力,是学习后续专业课程的基础。而截交线、相贯线几乎涉及了投影知识的所有知识点,是由基本体过渡到组合体的一个台阶,是这门课教学的重点和难点。文章从历年来学生现状和教学实际出发,对这部分教学的探索和实践进行了总结。 “Mechanical drawing” is a technical basic course for engineering colleges, which has both systematic theory and strong practicality. Mainly to develop students’ drawing and drawing ability, is to learn the basis for follow-up professional courses. Intercept line, the intersection line involves almost all the knowledge of projection points, is the transition from the basic body to the assembly of a level, is the focus of this course teaching and difficulties. Based on the status quo of students and teaching practice over the years, the article summarizes the exploration and practice of this part of teaching.