Most of SO₂,NO₂ and O₃ monitors in the measurement network are point monitors at ground level that yield no information about the spatial distribution of SO₂,NO₂and O₃. The information is conventionally obtained with ballon-borne sensors. However,this method provides only poor temporal and spatial resolution. A mobile differential absorption lidar(DIAL)system for atmospheric pollution measurements has been developed at the Anhui Institute of Optics and Fine Mechanics,the Chinese Academy of Sciences. It allows 3D-measurements by using a steering unit,and can measure four kinds of pollutants in atmosphere,SO₂,NO₂,and O₃. By using this lidar system,SO₂,NO₂ and O₃ measurements have been performed in Bejing from December 27,2001 to January 27,2002.It was the first measurement of air pollution monitoring in Beijing by DIAL. Comparison with the simultaneous measurement performed with SO₂,NO₂ and O₃ analyzers showed good agreement.