Abstract: Acid deposition flux of precipitation was developed, and with the support of ARC/INFO, its spatial distribution was calculated on the basis of the spatial distribution of total acidity and annual precipitation amount. The results show that the distribution of acid deposition flux and acidity of precipitation are similar, and Middle China and South China receive the most acid import. Organic acids are the most important weak acid-base components in precipitation. According to the background concentration of organic acids in precipitaiton, their contribution to acid deposition flux was also calculated.