Abstract: Using non-radial weighted Russell directional distance function, this paper first calculated the air pollution emission efficiency of 11 provinces from Yangtze River Economic Zone, and then investigated the trend of efficiency from 2007 to 2014. Theil index was adopted to explain the reasons for regional differences of air pollution emission efficiency of Yangtze River Economic Zone. Furthermore, the system generalized method of moments(SGMM)was used to investigate the determinants of air pollution emission efficiency. It was found that the air pollution emission efficiency of Yangtze River Economic Zone was relatively low and kept declining in recent years, indicating the large potential of air pollution emission reduction. The efficiency gap between the upstream, midstream and downstream areas and the internal efficiency gap of upstream areas were the key factors for the regional differences of Yangtze River Economic Zone's air pollution emission efficiency. Among the contributors to air pollution emission inefficiency of Yangtze River Economic Zone, ranked No. 1 was smoke and dust, followed by SO2, and ranked last was nitrogen oxide. Economic growth, increasing the proportion of the third industry, increasing investment in R&D, optimizing energy consumption structure, and raising the level of opening to the outside world could significant promote the air pollution emission efficiency of Yangtze River Economic Zone.