二面角是高中立体几何中一个重要的问题,是历年高考的一个热点,但也一直是学生学习的一个难点。突出表现在:一是视角识别困难;二是考题中二面角平面角的作法选择难。本文针对这两点归纳出两类常见的模型及两种求二面角大小的特殊技巧来解决这些难点。 Dihedral angle is an important issue in high school three-dimensional geometry, is a hot spot for college entrance examination over the years, but it has also been a difficult point for students to learn. Prominent in: First, perspective recognition is difficult; Second, the test questions in the dihedral angle plane approach difficult choice. In this paper, two kinds of common models and two special techniques to find the dihedral angle are summarized to solve these difficulties.