Abstract: To study the characteristics of air quality changes and meteorological factors of the capital cities in Northwest China from 2017 to 2021, the method of Spearman's rank correlation coefficient and Pearson Correlation Coefficient were used, based on the air quality monitoring results and meteorological observation data of the same period deducting the impact of sand weather. Meteorological factors had different effects on pollutants concentration and cities. Air pollutants concentration of Xi'an, Lanzhou and Yinchuan had stronger relation with air temperature and pressure. Air temperature and precipitation had effect on air pollutants concentration of Xining. Air temperature,relative humidity, wind speed and sunshine hours affected pollutants concentration of Urumqi.