本文给出了三维刚体与刚体完全弹性碰撞中，动能不损失等价于恢复系数e=1的证明，推广了以往在质点间碰撞、质点与刚体碰撞中得到的结果的适用范围.本文避开了碰撞中刚体转动能量的计算，以冲量和做功入手完成了一种简单的证明.

This article provides a proof that the non loss of kinetic energy is equivalent to the recovery coefficient e=1 in a fully elastic collision between three-dimensional rigid bodies. This article extended the applicability of previous results which obtained in collisions between particles, and collisions between particle and rigid body. This proof avoids the calculation of rotational energy of rigid bodies, and completes a simple proof by starting with impulse and work done.