The synthesis theory of the accelerations of points on rigid body that revolves round axle of intersection are proved with method of geometry. The cause of physic that bring accelerations of coriolis is directly observed.

• 对于定轴转动时的牵连运动,点的加速度是直接对动点的绝对速度的矢量表示式进行求导而得到,现用几何法证明了刚体绕相交两轴转动时,刚体上点的加速度合成定理,并可以直观地看到科氏加速度产生的物理原因。