Abstract: The phenomena of light scattering often occur in the natural environment.The Mie scattering theory, which is derived from the Maxwell equations,exactly represents the distribution of scattered light. The refractive index of mediums is directly related to the distribution of scattered light. And it is very important to carry out a qualitative analysis and a quantitative analysis. In this paper, by means of experimentations and numerical analyses, it is confirmed that the real part variation of the refractive index of mediums influences the distribution of irradiance intensity less than the imaginary. This result can be used for many studies which base on the distribution of scattered light.