In the present paper, the importance of base cations in acid precipitation in China, especially the effects of base cations on soil acidification, has been assessed in three aspects: comparison of chemical composition of acid rain between two cities in southern China and two cities in Europe, batch experiments of forest soils from southern China, and forecast of MAGIC model used in Guiyang catchment. The results show that high contents of base cations (Ca2+ , Mg2+ , , etc.) in the acid rain in China could not only neutralize the acidity of acid rain, but also reduce acidification of soils. Although leading to opposite results, base cations and acidic anions (, , etc.) in acid rain are the two important factors affecting soil acidification.