Abstract: The improvement of atmospheric environmental quality has always been a matter of concern. Using the monitoring data of Shanghai air quality monitoring station, the concentration distribution characteristics and influencing factors of PM_2.5 in shanghai is analysed. The results show that the PM_2.5 concentration in Shanghai has been decreasing in the past six years, with an obvious average annual decrease rate and an average annual change range. At the same time, the concentration distribution of PM_2.5 also varies with the seasons. This paper also analyzed the correlation between PM_2.5 and temperature, relative humidity, average air pressure and daily accumulated precipitation at the level of 0.01. In terms of social and economic influencing factors, there is a serious multicollinearity between the proportion of primary industry, secondary industry, tertiary industry and residents' consumption level and other factors. Except for environmental protection investment, other social factors have no significant correlation with PM_2.5 concentration.