Abstract: In order to restore forest vegetation destroyed by pine wilt disease, make full use of its’ ecological function, water samples including atmospheric precipitation, through fall, stem flow, litterthrough and soil solution were collected from different type stand in Zhoushan Island. The pH and several ions such as Cl^-, NO^-₃, SO^2-₄, Na⁺, Mg²⁺, and K⁺ of water quality index were detected. The results showed that: ① pH value decreased and contents of several ions increased in the process of the atmospheric precipitation forming throughfall and stem flow, thus adsorbate on the surface of branches, leaves and stems was the most important factor. ② pH value significantly increased in the process of through fall and stemflow forming litterthrough, therefore, litter layer has large regulation function on pH value. SO^2-₄ content decreased, so we could draw a conclusion that litter layer had a large adsorption effect on SO^2-₄. Other ions contents increased, especially for NO^-₃ and K⁺, the reason was that NO^-₃ and K⁺ in the litter layer by microbial decomposition were leached out. ③ pH values of litterthrough and soil solution were close, but content of Cl^-, SO^2-₄ and K⁺ decreased significantly in the process of litterthrough forming soil solution. It could be concluded that soil layer had a larger adsorption effect on Cl^-, SO^2-₄, and K⁺. Therefore, the litter layer and soil layer were the most important for purifing water of forest ecological system. ④ pH value of water in broad-leaved forest and mixed forest was slightly higher than other forest types. Broadleaf litter was more prone to decompose than conifer, the ion adsorption efficiency of litter layer and soil layer in broad-leaved forest was higher than that of conifer, so that we could conclude that water purification efficiency of the broad-leaved forest and mixed forest was higher than coniferous forest.