Abstract: The contents of ten forest precipitation chemistry indexes (pH, NH+4N, Ca2+, Zn2+, etc.) in different hydrological process (precipitation, throughfall, stemflow, litterthrough, runoff and subsurface flow) of four vegetation types (Masson pine forest, Quercus variabilis forest, Chinese chestnut forest and Pineoak mixed forest) in Lanlingxi small watershed in the Three Gorges Reservoir Area were studied. The results shown that: (1)The maximum content in precipitation was Ca2+, and the second to fourth ones were Na+, TN and NH+4N,respectively,and the minimum content was TP. (2) The hydrochemical characteristics changed obviously after the rainfall passed through the forest canopy, and acidification was found in the throughfall and stemflow in different forest. The leaching coefficient of K+ and TP were mostly higher than other elements of different hydrological process. K+ and TP were easily to be leached. (3)The contents of ions(Ca2+, K+, NH+4N and TN) were easily to be leached in throughfall in different forest. The net leaching amount of trace elements( Zn2+, Mg2+, Fe3+ and TP) have less change, and even absorbed. In stemflow, the contents of ions(Ca2+, K+, NH+4N and TN) increased significantly, and the content of Ca2+ was absorbed by trunk stem of broadleaf forest. The pH was increased in litterthrough, and the acid ions were neutralized by nutrient in litter. The pH of runoff was higher than precipitation, surface layer has important catabatic effect to acid in precipitation. The contents of ions(K+ and Ca2+ ) were increased obviously in runoff. The contents of ions (NH+4N and TN) in Pineoak mixed forest and Chinese chestnut forest were absorbed in runoff as well as the contents of Zn2+ in Masson pine forest and Quercus variabilis forest. The pH of subsurface flow was lower than runoff. The contents of ions(Ca2+ and K+) were increased obviously in subsurface flow. The contents of ions(NH+4N and TN) had negative eluviation effect in all forest.