【摘要】 本文介绍一个关于透视图椭圆的定理。在中心投影和平行投影之间建立一种对应关系，在中心投影下把圆变成椭圆，但是不能确定椭圆的共轭轴或长轴与短轴的位置和长度，该定理解决了这个问题。在理论上，为计算机绘制透视图椭圆时使用现有通用椭圆程序提供了新的根据。更多还原

【Abstract】 The theorem of ellipse in perspective drawing is introduced in this paper. Found a kind of internal relation between the center projection and the parallel projection, under the center projection, the circle is changed into ellipse, but it can’t decide the relation between the conjugate axis or major axis and minor axis of ellipse, which can be solved by this theorem. Theoretically, it provides a new evidence for computer to use program of ellipse avalilable to draw ellipse in perspective drawing.更多还原