Based on atmospheric particles and conventional meteorological data from Feb.8 to Feb.19 of 2013 in Hefei, according to the discharge of fireworks, type of precipitation, relative humidity and wind speed characteristics, the variation characteristics of PM2.5 mass concentration in different meteorological conditions were analyzed. The results showed that: during the Spring Festival in Hefei the average value of PM2.5 mass concentration was 58.3 μg/m3, PM2.5 mass concentration pollution occured only two days. PM2.5 mass concentration, caused by urban residents concentrated fireworks discharge, increased rapidly, but the discharge are mostly ultrafine particles (PM1). PM2.5 mass concentration of precipitation with wet deposition effect, the greater the precipitation process is, the greater the amount of wet deposition of PM2.5 mass concentration will be. Different size scales particles have different hygroscopic growth characteristics, and the correlation coefficients of PM1, PM1～2.5 and PM2.5～10 and relative humidity were 0.45, 0.26 and －0.07. The smaller the size scale particles is, the more obvious the hygroscopic growth properties will be. Evolution of PM2.5 mass concentration was negatively correlated with wind speed, the correlation coefficient is －0.33. The greater the wind speed is, the greater the diffusion capacity of particulate matter will be.