Abstract: Based on the meteorological observation data and particulate matter data of Deyang during the period from 2014 to 2021, the variation characteristics of PM_2.5 and PM₁₀ concentration and the correlation with meterological factors were analyzed. Taking the pollution process of PM_2.5 from January 25th to 28th, 2017 as example, the weather condition and backward trajectory were carried out. The results showed that: (1) The concentrations of PM_2.5 and PM₁₀in Deyang showed a downward trend from 2014 to 2021. The daily maximum and minimum concentrations of PM_2.5, PM₁₀ appeared at 11 : 00 and 17 : 00, respectively. The monthly average concentration showed the characteristics of "low in summer and high in winter". (2) The daily average concentrations of PM_2.5, PM₁₀ in all seasons were significant negatively correalted with precipitation and surface wind, while there were seasonal differences in the correaltion with relative humidity, pressure, temperature. (3) The stable weather conditions such as continuous uniform pressure field, small pressure gradient, light breeze and the input of upstream pollutants were the main factors leading to the formation and aggravation of this heavy pollution event.