基于平方反比有心力作用下的质点的束缚态椭圆轨道运动的开普勒运动规律，以及机械能守恒律与角动量守恒定律，计算了质点的椭圆轨道运动的一些特征参量（速率、极半径、转动惯量、角速度、动能、势能等）的周期平均值，并证明了若干均值关系，讨论了2个典型的均值特征点. 根据计算所得的椭圆轨道的动能、势能等特征量的周期平均值，直接证实了位力定理，最后讨论和强调了这些均值关系之于物理教学的参考意义.

 Based on Kepler's three laws, and the conservation laws of mechanic energy and angular moment about a mass point moving on an elliptic trajectory under an inverse-squared centric force, the mean values within a period of some typical physical quantity (polar radiurs，speed, angular speed, angular momentum, rotation inertia, kinetical energy，potential energy，and so on) ，are calculated and several interesting and useful mean-value relations are found and proved. A unique mean-value point on the path of the mass point is emphasized. The Virial theorem is direct proved by means of these calculated mean values. The physical meanings, and teaching reference significance of these findings are also emphasized.