This research was carried out to investigate the effects of the different tree species(Q. spp., L. leptolepis and P. koraiensis) about the chemical properties of throughfall and stemflow, to purify the acid rain at Kyung Hee Univ. experimental forest, Gwangju-gun, Kyunggi-do. The water quality of the precipitation, throughfall and stemflow in each forest stands were analyzed chemically. The throughfall pH ranges were Q. spp.(pH 4.96-6.34), L. leptolepis(pH 3.96-6.41) and P. koraiensis(pH 4.11-6.36), and the stemflow pH ranged Q. spp.(pH 4.33-6.05), L. leptolepis(pH 3.59-6.09) and P. koraienszs(pH 3.60-6.13). pH values of throughfall and stemflow to the precipitation were Q. spp. Niger than L. leptolepas and P. koraiensis, while distribution range was small. Therefore, buffering capacity about the precipitation in the tree species trended Q. spp. bigger than L. leptolepr`s and P. koraiensis. Nearly all concentration of dissolved elements were precipitation≤throughfall≤stemflow. The cation (Ca^(2+), Mg^(2+), K^+ and NH₄^+), and anion(Cl^- and NO₃^-) were increased. Especially the concentration of Mg^(2+), K^+, NH₄^+ and Cl^- were noticeable. In comparing concentration of dissolved elements of throughfall with each tree species, Ca^(2+) concentration was Q. spp. $lt; P. koraiensis=L. leptolepts and NH₄^+ was Q. spp. $lt;P. koraiensis$lt;L. leptolepis.