Abstract: The numerical algorithm of Mie theory was realized in IDL. The scattering efficiency and phase matrix elements of black carbon and dust aerosols at 400nm and 860nm wavelength were calculated when their radius were 1m，2.5m and 10m. The results show that the optical characteristics of the black carbon and dust are significantly different, and both the scattering efficiency and backward scattering of the dust are greater than those of the black carbon. Since the lighting polarizations of the two aerosols are different at the sun light of 400nm and 860nm, both the aerosols can be distinguished with the characteristics.