Based on some analyses on spectral irradiance measured with the Sun-A tmosphere Ultraviolet Spectrum Radiometer (SAUVS) developed by the Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing and the results calcula ted by means of radiative transfer models UVSS, the influences of various import ant factors affecting UV irradiance reaching the ground surface, such as solar z enith angle(SZA), ozone column amount and ground surface albedo were evaluated. Then total amount and spectral analyses were made on data of ultraviolet spectro radiometer.