The severe haze pollution has become one of the major obstacles to the ecological integration development of the Yangtze River Delta (YRD).This paper constructs a haze control efficiency evaluation system taking labor, capital and technological innovation as input indicators, and the number of days with air quality at or better than level 2, PM_2.5 concentration and AQI as output indicators, and uses a three-stage DEA to measure the haze control efficiency of 27 cities in the YRD from 2014 to 2019.The results show that the three-stage DEA model can effectively remove the influence of environmental factors and random errors, and can truly reflect the level of haze control efficiency in the YRD.The change of return to scale is significantly influenced by environmental and random factors, and most cities are in the stage of increasing return to scale.The overall haze control efficiency of YRD cities from 2014 to 2019 is high and shows a W-shaped change trend, with significant inter-city differences.The GDP per capita and the share of secondary industry have a positive effect on haze control efficiency, while population size and urbanization rate have a negative effect on haze control efficiency.