正投影法中的重要内容之一是图解法。它可以形象、简捷的使三维空间几何问题在二维平面上求解;但其缺点是精度低,不适应工程技术上的要求;随着计算技术的发展,图解法与解析法相结合已是图解法发展的一种趋势;本文简要介绍图解法的发展史以及与解析法相结合的必要性和形式,以便正确认识图解法及应用图解法为工程技术服务。 One of the important aspects of orthographic projection is graphic method. It can be image, simple and easy to make the three-dimensional space geometric problems in the two-dimensional plane to solve; but its disadvantage is low accuracy, does not meet engineering and technical requirements; With the development of computing technology, the combination of graphic and analytical method is the graphic method This article briefly introduces the history of the development of graphic method and the necessity and form of combining with the analytic method in order to correctly understand the graphic method and apply the graphic method to serve the engineering technology.