用空间向量知识解决立体几何问题的优势是不必添加繁杂的辅助线,使问题坐标化、符号化、数量化,这一机械的解题方法易于被学生接受和掌握,劣势在于,遇到不规则的空间图形时学生往往不知道如何建立空间直角坐标系.如果坐标系建立得不合理,在读取空间点的坐标时极易出错.如何合理地建立空间直角坐标系,本文将针对这一问题介绍笔者的观点.一、共点的三条直线两两垂直 The advantage of using spatial vector knowledge to solve the problem of solid geometry is that it is not necessary to add complicated auxiliary lines to coordinate, symbolize and quantify the problem. This mechanical problem solving method is easy to be accepted and mastered by students. The disadvantage is that when encountering irregularities Of the spatial graphics often do not know how to create space Cartesian coordinate system.If the coordinate system is set up unreasonably, when reading the coordinates of the space point error-prone.How to establish a reasonable rectangular space coordinate system, this article will address this issue Introduction of the author’s point of view. A total of three straight lines two two vertical