Based on the differential optical absorption spectroscopy (DOAS) technology, measurements of atmospheric pollutants were carried out continuously in August. 2007 at Chaoyang District,Beijing. Diurnal variation characteristics of pollutants and sources are analyzed. And relations between pollutants and meteorological conditions are discussed. Moreover, the concentrations of NO2, SO2 and O3 in the period of “Good Luck Beijing” Olympic test games (traffic ban August 17-20 and no traffic ban August 16, 21) are given emphasis to analyze. Results indicate that automobile exhaust is the main source of NO2, and the concentration of NO2 is high in the a.m. and wee hours. It can also be found that NO2 contributes part to the O3 formation. SO2 came mainly comes from the southwest and the concentration of SO2 decreased with the north wind. Traffic ban reduces the levels of NO2,SO2 of 28.34％ and 25.87％, respectively,but the levels of O3 increase.