1359 samples were collected from 18 May, 2013 to26 May, 2014, in the suburb Nanjing,China.We analysed the water-soluble ionsand found that:secondary inorganic aerosols (NH4+,SO42-and NO3-)are main components in the inorganic ions, annual average was 17.2, 18.5 and 17.1μg·m-3respectively, 20.9%, 22.5%, 20.8% of the total inorganic aerosols.It is defined as the Normal Days when visibility distance is more than 7.5 km, orit is Haze Days.In Haze Days, ions concentration increased significantly in the fine size (Particle size is less than 2.1μm).Especially, NH4+,SO42-and NO3-had increased by 52.6%, 71.3% and 73.1%.While ions concentration increased slowly in the coarse size (Particle size is 2.1-10μrn).Especially, NH4+, SO42-and NO3-had increased by 14.7%,27.2% and 54.5%.In fine size, the concentration rise of NH4+ in spring Normal Dayswas related to farmland emissions.In winter, SO42-and NO3-was 22.0 and 17.7 μg·m-3, maximum during the year,which was related to coal emissions,but it was not the main cause of pollution.In Haze Days,the proportion of NH4+dropped by 3.4%, the main composition were NH4NO3 and NH4HSO4.