Abstract: Effective absorption of internal mixed aerosol has severe negative effects on laser transmission in atmosphere. The effective absorption coefficients of homogeneous sphere model, BC-core model and NaCl-core model aerosols, with the same density and specific heat of particle, were discussed by Mie theory. Results show that effective absorption is associated with comprising method. The BC-core sphere particles mainly show superior effective absorption at short wavelength as visible light and infrared light, homogeneous sphere particles mainly super at mid-infrared wavelength and far-infrared wavelength after 100 s, while NaCl-core particles mainly show larger effective absorption coefficient at far-infrared wavelength at beginning of heating procedure.