Based on the aerosol scattering properties observed by the integrating Nephelometer in the north suburb of Nanjing in spring 2011,combined with data of PM_2.5 mass concentration,visibility and routine weather observation,the variation features of aerosol scattering coefficients and its correlation with PM_2.5 mass concentration and visibility were analyzed.Results show that the mean aerosol scattering coefficient is 311.5±173.3 Mm^-1 and the maximum frequency distribution of hourly mean scattering coefficient is 100-200 Mm^-1.The diurnal variation of aerosol scattering coefficient is obvious,and higher(lower) in the morning and evening(at noon and in the afternoon).The trend variation of scattering coefficient shows an agreement with the mass concentration of PM_2.5,and a negative correlation with the visibility.The daily mean aerosol scattering coefficient in the hazy day is up to 700.5±341.4 Mm^-1,and the maximum value reaches about 1 900 Mm^-1.The analysis of ground observations,NCEP/NCAR reanalysis data and simulated back trajectories of air parcels shows that the air parcels mainly come from south and southeast of Nanjing in the hazy day.