On the basis of the known conical section, the essay discusses the methods of sector constructing for apex and focus of conical section by deciding the center of conical section.

• 摘要本文在已知确定圆锥曲线的基础上，通过确定圆锥曲线的中心和顶点，给出了圆锥曲线焦点的尺规作图方法。