1　设计课题的选择数学研究的对象是现实世界的空间形式和数量关系 .立体几何在形成学生的空间概念、培养学生空间想象能力、思维能力的重要作用是中学数学其它内容所不能替代的 .而高中学生普遍对立体几何的学习感到困难 ,究其原因主要有 :刚步入高中的学生的实际感知及所有具 1 The choice of design topics The object of mathematics research is the spatial form and quantity relationship of the real world. The three-dimensional geometry plays an important role in forming the spatial concept of students, cultivating students’ spatial imagination and thinking ability, which cannot be replaced by other contents of middle school mathematics. High school students generally find it difficult to learn three-dimensional geometry. The main reasons are: the actual perception of students who have just entered high school and all