Abstract: In order to provide the basis for air pollution meteorological condition and air quality forecast, the influence of meteorological factors, such as average daily wind speed, average daily ground temperature, average daily vapor pressure, average daily air temperature and average daily relative humidity, on the air quality index （AQI） was studied by grey correlation analysis based on the meteorological observation data collected by meteorological bureau and the AQI released by environmental protection department in the spring （from March to May） of Hohhot. The result showed that the meteorological factors were able to influence the AQI. The impact of the factors on the AQI was average daily wind speed〉average daily relative humidity〉average daily vapor pressure〉average daily air temperature〉average daily ground temperature.