从对称性的角度，分析了光波在无限大均匀介质中、两种媒质的分界面上传播必须遵从的时间和空间平移不变性，推导出光的直线传播、反射以及折射定律，揭示了支配几何光学三定律的更为深刻而底层的对称性原因，这种视角对于光学部分的教学将产生深刻的影响.

The space and time symmetrical properties of optical wave and the medium have been analyzed. According to the symmetry principle the time translation symmetry and some of the space translation symmetry have to be preserved during light propagation，reflection and refraction processes，and the three geometrical optic laws of rectlinear propagation law，reflection law and refraction Snell’s law are derived. The symmetrical analysis here explicit that the symmetry principle is of fundamental importance and is the basement governing the optical processes.