In order to improve the air quality during the 2008 Olympic Games, Beijing government had took a series of temporary measures, such as traffic management and close of factories during the period of the Olympic Game from July 20 to September 20, 2008. Those measures had a significant effect on reducing smoke and dusts emission. For reducing the emission by 30% after the standard achieved, 19 key enterprises and 4 coal-burning power plants reduced production, adjusted operation modes, pollution managements and implemented some other measures during the Olympic Games. The strictest emission limit of coal-fired boiler was carried out since 1st July, 2008. More than 150 heavy polluting enterprises were shut down, reduced production or limited production in order to control industry pollution. Otherwise, prohibition of earthworks and concrete pouring projects in urban during the Olympics also reduced the pollution. Green ways of travel such as taking different working hour, choose the public transportation journey, could further reducing the sources and accumulation of PM2.5 ,NOX,CO.In this paper, the concentrations and their dynamics of three main air pollutant, including PM2.5, NOX and CO, were analyzed based on the monitoring data from the Beijing Urban Ecosystem Research Stations. The average concentration of CO at the Research Center of Eco-Environmental Sciences (RCEES) and Beijing Teaching Botanical Garden (BTBG) reached the first class standard of our country both during and after the period of the Olympic Games, meanwhile PM2.5 average concentration exceeded the American national standard. The average concentration of PM2.5, NOX and CO at the Research Center of Eco-Environmental Sciences (RCEES) were 0.060 mg/m3, 0.065 mg/m3and 0.065 mg/m3, respectively, while the average concentration were 0.07 mg/m3, 0.03 mg m-3 and 1.10 mg/m3, respectively, at the Beijing Teaching Botanical Garden (BTBG). Their concentrations were obviously increased after the Olympic Game. The concentrations of PM2.5, NOX and CO raised by 3.3％, 76.9% and 56.5% at the RCEES, and by 58.8％, 56.7% and 163％ at the BTBG, respectively. The quantity and concentration of PM2.5,NOX,CO showed double peaks appeared at 7:00-10:00 and 18:00-23:00, respectively according with the normal daily dynamics of air pollution. Weather conditions and traffic emission were supposed to be the key factors contributed to this phenomenon, especially the emission from the growing number of cars in rush hours. There was no significant correlation between the three air pollutant concentrations and the meteorological factors except that the hourly average PM2.5 concentration at the RCEES was significantly correlated with the hourly mean temperature and wind speed. No significant correlation between the daily average concentration of PM2.5 and weather condition mentioned above were observed neither before nor after the Olympic Games. Weather conditions during the whole period of Olympic Games were not improved comparing with the weather conditions before the Olympic Games. However, average concentrations of PM2.5 ,NOX,CO during the period of the Olympic games were significantly lower than the average concentrations after the Olympic games. Our monitoring results suggested that the temporary air pollution control measures during the 2008 Olympic Game were effective.