本文对《大学物理》论文“自由空间中平面电磁波的电场和磁场总是同相位吗？”中讨论的问题进行了重新讨论.结果表明关于平面电磁波的电场强度E、磁场强度H可能反相位的观点是没有必要的，“同步”和同相位亦无本质区别，传统教材中认为自由空间中平面电磁波的电场与磁场总是同相位的观点并无问题.

This paper reexamines the issue discussed on the paper titled "Are the electric and magnetic fields of plane electromagnetic waves in free space always in phase?" in College Physics. The results demonstrate that the viewpoint suggesting possible phase opposition between the electric field intensity E and magnetic field intensity H in plane electromagnetic waves is unnecessary. There is no essential difference between the "synchronization" and the same phase, confirming that the traditional viewpoint presented in textbookswhich maintains that the electric and magnetic fields of plane electromagnetic waves in free space are always in phaseholds true without exception.