The complex refractive index is an important optical constant, which is usually used to describe some optical properties of absorptive media. The extinction efficiency factor is calculated by the ratio of the extinction cross section of the material particle to the maximum cross-sectional area of the particle. It is numerically equal to the sum of the scattering efficiency factor and the absorption efficiency factor and is often used to characterize the optical attenuation properties of optical attenuation materials. In the present study, the complex refractive index of optical attenuation materials is often calculated by spectral testing and Kramers-Kronig algorithm and the extinction efficiency factor of materials is obtained by calculating the single scattering parameters by discrete dipole approximation. However, the effects of complex refractive index of the optical attenuation material on its extinction efficiency factor have not been studied. It is meaningful to study the effects of complex refractive index on extinction efficiency factor, which can further study the relationship between the attenuation properties of optical attenuation materials and their material properties.