本文给出关于三角形垂心的一个新性质:定理三角形的垂心与其关于三边的对称点关于三边中点的对称点,凡此四点共圆,其圆心是三角证形明的外心,半径是三角形的欧拉线长·设O和H是△ABC的外心和垂心,D、E、F分别为三边BC、CA、AB的中点,且记垂心H关于三边BC、CA、AB的对称点为Hi(i This paper gives a new property about the vertical center of a triangle: the symmetry point of the center of the triangle of the theorem and its symmetry point about the three sides about the midpoint of the three sides. Where these four points are co-circular, the center of the circle is the outer center of the triangle. The length of the Euler’s line is triangular. Let O and H be the outside and center of the △ABC. D, E, and F are the midpoints of the three sides BC, CA, and AB, respectively. Let’s note the vertical center H about the three sides BC, CA, and AB. The symmetrical point is Hi(i)