平面几何中,关于三角形有不少著名的富有趣味性和启发性的定理,例如关于外心、重心和垂心共连(Euler线)的定理,关于三角形外接圆上的任意点在三边上的射影共线(Si mson线)的定理,等等[1,2].本文将要提出并证明的是关于三角形外心和内心的连线的一个特殊性质,见下面的定理1.定理 In plane geometry, there are quite a few notable and interesting theorems about trigonometry, such as the theorems about the outer, centroid, and centripetal (Euler lines), the theorem about any point on the triangle circumcircle on three sides The theorem of Si mson line, etc. [1, 2] .This paper will present and prove a special property about the connection of the outer and inner triangle, see the following Theorem 1. Theorem