如果圆锥曲线的一条弦所在的直线经过焦点,则称此弦为焦点弦.圆锥曲线的焦点弦问题是解析几何中的重点,也是难点,更是各类考试命题的热点.解此类问题,如果采用列方程求交点的方法,虽然步骤清晰,但运算量大,且易出错.本文介绍圆锥曲线有关焦点弦问题的两个重要公式及其应用,可明显减少计算量,提高解题速度. If a straight line of a conic curve is the focus of the line, then the string is the focus string. The focus of the conic curve string problem is the focus of analytical geometry, but also difficult, but also all kinds of test proposition hot spots. Such problems, If the method of intersection of column equations is adopted, though the steps are clear, the computational complexity is large and error prone.This paper introduces two important formulas and their applications of the conic curvilinear focus problem, which can significantly reduce the computational complexity and improve the speed of problem solving.