本文在研究各向同性介质的基础上，分别对复折射角和复波矢两种方法进行考察，并从折射角和菲涅耳系数方面证明了这两种方法的等价性. 我们进一步利用时域有限差分法数值模拟了损耗介质中的电磁波传播过程，验证了理论分析结果的可靠性.更有趣的是，与无损耗介质折射不同，电磁波在斜入射到损耗介质后可能存在不改变传播方向的情况，即折射角可以等于入射角.这些分析不仅有利于理解电磁波在无损耗介质-损耗介质中的传播规律，也对电磁学知识的学习与应用有所帮助.

The electromagnetic wave after refraction can change its phase propagation direction as well as its amplitude in lossy media. Conventional textbooks usually treat the problem in terms of complex refractive angles or complex wave vectors. However, these complex concepts lack geometrical or physical significance, and the intrinsic relationship between these two treatments is less discussed. In this paper, based on the study of isotropic media，the two methods are discussed in detail and their equivalence is proved from the perspective of refraction angle and Fresnel coefficient. Numerical simulation by the finite-difference time-domain method verifies the reliability of the theoretical analysis. More interestingly, the electromagnetic wave may not change its propagation direction after oblique incidence into a lossy medium. These analyses not only provides a clear understanding of the laws of electromagnetic wave propagation in lossy media, but also helpful on the teaching of electromagnetism.