The concentration distribution of CO in Beijing based on MOPITT data and instrumental dataset was analyzed. The results showed that CO column concentration reflected the contamination level of the territorial air pollution, and near-ground CO mass concentration was mainly due to local air pollution emission. As for the continental background CO column concentration of Waliguan was similar to seasonal variations of near-ground mass concentration. CO column concentration reached its peak in spring, but mass concentration near the ground surface was higher during heating period when compared to no-heating period in Beijing. CO column concentration during August of 2000[EQUATION]2007 increased slowly but mass concentration near the ground surface decreased significantly in Beijing. Air cleaning measures taken during 2008 Beijing Olympic Games considerably reduced about 19.3% column concentration and 46.7% mass concentration of CO due to decreased emission of air pollutants from Beijing and its circumjacent regions. It can be concluded that the air cleaning measures greatly improved air quality, but the distribution of air pollution is still kept as it is.