During the measurement of atmospheric trace gases with zenith-sky scattering light observations, the absorption feature of O4 in the ultraviolet-visible region can affect the results. The principle, equipment and method of measurent, as well as the processes of spectra analysis and concentration retrieval are presented in detail. Experiment proves that the accuracy of NO2 and O3 retrievals can be improved when considering the profile of O4 absorption. A brief comparison between our ground-based experiment results of ozone vertical column density with that measured by TOMS is also given in the last part of article.