The back-scattering ofRayleigh scatter model and Mie scatter model is analyzed, and the scattering phasefunction of various aerosol models is discussed and calculated. A back-scattering modelbased on laser illuminating is set up, and the actual back-scattering affect function isprompted, also the analytical express is given. Under actual atmosphere, the disturbanceof laser illuminating by back-scattering is measured by CCD camera, and the model is tested.