Abstract: Studies on the chemical properties of precipitation, throughfall, stemflow and surface run off in major forest types at Dinghushan under acid deposition showed that the pHvalue of precipitation was about 4.90,and the frequency of acid rain was over 62%. In broad leaved forest, the pHvalue of precipitation was lower than that of throughfall, but higher than that of stemflow and especially the surface run off, indicating that the soil was naturally acidified. In mixed forest, both throughfall and surface run off had a higher pHvalue,but stemflow had a lower pHvalue than precipitation. The throughfall and stemflow were more acidified than precipitation in coniferous pine forest, but the surface run off had a higher pHvalue than precipitation. These results suggested that among the three major forest types at Dinghushan,the canopy of broad leaved forest had the highest buffering ability,whereas for the soil,the coniferous forest had the highest soil buffering capacity. The concentrations of nutrient elements, such as P, K, Ca, Na and Mg in the throughfall, stemflow and surface run off were higher than those in bulk precipitation in all forests at Dinghushan, some even 10 times higher, indicating that a large amount of nutrients were leached from the canopy. The concentrations of nutrient elements in stemflow were higher than those in throughfall in all forests, and the concentration of nutrient elements in surface water was higher than those in atmospheric rainfall. Coniferous forest had a higher concentration of nutrients in the throughfall and stemflow and a lower nutrient concentration in the surface run off than other forest types,which implied that nutrient loss was more serious in broad leaved and mixed forests than in coniferous forests.