In this paper, refraction behaviors of light in both metal single-layered film and metal–dielectric–metal multilayered films are investigated based on the generalized formulas of reflection and refraction. The obtained results, especially, dependence of power refractive index on incident angles for a light beam traveling through a metal–dielectric–metal multilayered structure, are well consistent with the experimental observations. Our work may offer a new angle of view to understand the all-angle negative refraction of light in metal–dielectric–metal multilayered structures, and provide a convenient approach to optimize the devised design and address the issue on making the perfect lens.