Based on the daily air pollution index(API), primary pollutant, air quality assessment data of 86 cities in China during 2001—2011.issued by the State Environmental Protection Depart. ment, 1 1years of urban air changes in characteristics of the pollution were analyzed in this paper. And the results show that：API have slow down trend during 2001—2011 in China cities.air quality is improved step by step；Urban air pollution time and space distribution characteristics were obvious, PM 10 pollution is serious in the north and northwest area.Sulfur dioxide pollution embodied in north and northeast in China and southern parts of the city.The occurrence of nitrogen oxides mainly a Dpeared in the south and east.the frequency of inland cities is lower；The main pollutants of atmos. pheric occurred in the region with identity；there were great difference in the city, the southern cities of air quality is obviously superior to the northern.