Abstract: Based on the air quality index (AQI) and meteorological observation data from 2014 to 2016,the variations of air quality and main pollutants and the relationship between AQI and the main meteorological factors in Harbin were analyzed.The results show that the number of days reaching the good air quality level is the highest,accounting for 47%,that reaching the level of pollution accounts for 31% during this time.The air quality in 2016 is the best.The AQI index is lower in spring and summer,and significantly higher in autumn and winter.The best air quality is found in September and the worst time occurs in winter.PM_2.5 is the major pollutant causing air pollution in Harbin,followed by PM₁₀,NO₂,and ozone for 8 hours.The correlation between AQI and air pressure is positive and reaches the most significant level in autumn and winter.Wind speed shows mainly negative correlation with AQI,especially in winter.The relationship between temperature and AQI is disturbed by the changes in building heating.It shows a negative correlation in the time scales of annual,autumn and winter.However,it shows a positive correlation in the monthly scales.It has a negative correlation with precipitation,a significant positive correlation with relative humidity in winter and a negative correlation with relative humidity from May to September.