Abstract: To investigate the pollution characteristics of the PM in Nanchang City in 2013, the mass concentration, ratio of PM and its correlation with gaseous pollutants were analyzed by collecting the air quality data in real time at 9 air monitoring stations in Nanchang City. Meanwhile, the source of chemical components in PM_2.5 was analyzed using PCA-MLR model in the severely polluted autumn. The results showed that:(1) The annual concentrations of PM₁₀ and PM_2.5 were (115.4±39.1) and (69.1±26.8) μg/m³ respectively, both higher than the national secondary standard. The highest levels of PM₁₀ and PM_2.5 appeared at Petrochemical and Provincial Foreign Affairs Office, while the lowest PM₁₀ and PM_2.5 happened at Forestry Research Institute. The concentration of PM exhibited apparent seasonality, following the order:winter > spring and autumn > summer. The PM₁₀ and PM_2.5 levels failed to meet Grade Ⅱ standards in 25.48% and 36.71% of the whole year, respectively. The days of PM_2.5 level exceeding the new Grade Ⅱ standards in each quarter was higher than that of PM₁₀ level. (2) The diurnal variation of PM level was in the form of double peaks and double valleys, which was mainly influenced by human activities and boundary layer height. One peak was between 08:00 and 10:00, and the other was between 20:00 and 22:00. The hourly peak in the evening was higher than that in the morning, and the lowest occurred at 15:00. (3) The annual average ratio between the monthly mean concentration of PM_2.5 and PM₁₀ was 60.3%, and the highest reached 65.1% in winter. (4) Correlation analysis indicated that the monthly mean concentration of PM_2.5 had very significant linear correlation with PM₁₀, having the same source. There was significantly positive correlation between the daily mean concentrations of PM and NO₂, SO₂, CO₂ and the correlation in winter was stronger than that in summer and autumn, while the correlation between the mass concentrations of PM and O₃ had a significantly negative correlation throughout the year, and was stronger in summer and autumn than that in winter. This negative correlation can be explained by the reaction of O₃ with NO₂ which indicated that the secondary transformation of gaseous pollutants had a significant impact on the concentration of PM. (5) The largest source of PM_2.5 in autumn in Nanchang City was mixed pollution source of road dust and vehicle exhaust, followed by construction dust, fly coal combustion and smelting dust/biomass burning, with contributions of 40.9%, 35.8%, 12.4% and 10.9%, respectively. The overall results suggest that the pollution of PM_2.5 in Nanchang is more serious than that of PM₁₀, PM_2.5 has become the main component of air particulate matter pollution in Nanchang City, and the major pollution sources are urban dust and vehicle exhaust.