Abstract: The aerosol characteristics of Xiamen, including mass concentration, element concentration ,ion concentration, acidity and acidification-buffering capacity of aerosol for three kinds of particle diameter, was studied in spring of 1993. The results show that the mass concentration of aerosol in Xiamen is close to Class I of National Air Quality Standards, and the fine particle plays an important role； the content of Ca, Al, Fe, and S is high in aerosol; the distribution of NH+4 and SO^2-₄ is mainly in fine particle, Ca²⁺ and Mg²⁺ mainly exist in coarse particle, and their concentrations are lower than those in Southern China ； for the acidity of aerosol, the fine particle's is higher than the coarse particle's, but for the acidification-buffering capacity, the fine particle's is much lower than the coarse particle's.