Abstract: A measurement system was made with nuclear pore filter which were used to collect atmospheric aerosol particles. We measured the absorption coefficient of light with different pore size filters in 488.0, 514.5 and 632.8nm wavelength. The system has two laser beams: the information one which transfers through glass pipe, and the reference one which transfers directly through atmosphere. In this way the measurement system can well eliminate the effect of all kinds of measurement errors caused by the optical loss, circuit noises and power fluctuation. The system also can decrease the effect of scattering for more precise measurement by partly plating highly reflective membrane. The measurement precision also advances along with increasing time of aerosol collecting. The precision is 9.849×10