In this work, a method to determine atmospheric aerosol optical density from multi axis differential optical absorption spectroscopy (MAX-DOAS) observations was described. It basically utilizes the differential absorption structures of the oxygen collision complex (O4) in the UV and visible wavelength regions to derive information on aerosol optical properties. Based on radiative transfer model with appropriate aerosol single scattering albedo, asymmetry parameter and profile, atmospheric aerosol optical density was retrieved in an iterative process by comparison with measured O4 slant column densities at 360 nm. The retrieved value was verified through comparisons with sun photometer CE318.