The natural outdoor exposure test of building exterior wall coatings was carried out in the natural climate exposure field,whilst the artificial accelerated aging test was carried out in the laboratory.By investigating the change of optical properties of coatings with aging time,the data collected from natural climate exposure test and artificial accelerated aging test were statistically analyzed,and the correlation between simulated artificial accelerated aging test and natural climate exposure test was studied.The calculation of service life of coatings was discussed.