论述了光程和光程差在普通物理光学教学中的主要作用.通过讨论和分析指出，光程和光程差是贯通整个光学教学的重要脉络.在光学教学中从始至终突出、强调这条脉络是非常必要的.

The important significance of the path and path difference in course teaching of optics is discussed. 　Through analysis and discussion，it is pointed out that the path difference is the main channel for teaching optics. 　To address this main channel from the beginning to the end in teaching optics is very important and necessary.