Abstract: By applying non parameter method,this paper study seventy cities' pm2.5 efficiency in China,which show:Firstly,the average pm2.5 efficiency is 0.527,the major reasons leading to low pm2.5 efficiency lay on low industry efficiency,low urbanization and low traffic efficiency. Secondly,the pm2.5 efficiency,industry efficiency,traffic efficiency and urbanization efficiency of eastern city is higher than The central and western cities,but there is much room for improvement in the above four efficiency for all cities. Thirdly,the efficiency of pm2.5,industry,urbanization and traffic in cities of the Changjiang delta,the Beijing-Tianjin-Hebei delta and the Pearl River delta is higher than that of other cities. Fourthly,the efficiency of pm2.5,industry,development and traffic of the medium sized cities is higher than that of other sized cities,and the I type large sized cities is higher than the Ⅱ type large sized cities,colossal cities and mega cities. The pm2.5 efficiency of mega cities is the lowest.