Particle size distributions and complex refractive index are basic physical parameters to describe the atmospheric aerosol and also the basic parameters of remote sensing the atmospheric aerosol optical depth, which determines the accuracy of optical depth remote sensing. This paper studies the volume size distribution and the complex refractive index of atmospheric aerosols around Beijing inverted by the China Aerosol Remote Sensing Network in dust and haze days. The results reveal that the volume size distributions of atmospheric aerosol in both dust and haze days show a bimodal logarithmic normal distribution. The volume size distribution of the atmospheric aerosol particles in haze days takes up an approximately same proportions in the fine mode (01 to 1 microns) and coarse mode (1 to 10 microns). However, the coarse mode in the volume size distribution of atmospheric aerosol particles in dust days take up a much larger proportion than the fine mode with the coarse particles being dominant. By comparing the actually measured complex refractive index with all types of aerosol complex refractive index spectroscopic data in the HITRAN 2008 Database, we can find that within the actually measured 07 to 10 μm spectral range, the real and imaginary parts of sandlike particles are close to dust aerosols and water soluble particles are close to haze aerosols. If lacking complex refractive indexes in remote sensing, we can use those of sandlike particles and water soluble particles (02 to 40 microns) to approximately replace the dust and haze aerosols for ultraviolet and infrared remote sensing. The study provides a reference for dust and haze aerosol researches by using the quantifying ultraviolet and infrared remote sensing.