在解析几何中，研究曲线的相互位置关系和性质总是转化为研究相应的代数方程。韦达定理是代数方程中最重要的定理之一，在中学解析几何中不乏应用。我们在教学中有些粗浅的体会，写出来求教于同行。 In analytical geometry, the mutual positional relationships and properties of the study curves are always translated into the corresponding algebraic equations. The Weddah’s theorem is one of the most important theorems in algebraic equations. There are many applications in the analytical geometry of middle schools. We have some superficial experience in teaching, writing out to seek advice from our peers.