Abstract:This article researches the influence of acid rain stress on leaf litter decomposition of dominant trees (Pinus massoniana Lamb., Schima superba Gardn.et champ, Cyclobalanopsis glauca (Thunberg) oersted）in subtropical regions of China. The purpose of this report is to analyze the effect of acid rain on litter decomposition through control experiment. There are three pH value were set up for the experiment, include pH5.6, pH4.0 and pH2.5. The net bag of leaf litter placed on the ground to simulate natural conditions. The results show that acid rain plays an important role on the leaf litter decomposition of three dominant trees in the subtropical forests. The decomposition rate under pH values 5.6, 4.0 and 2.5 of acid rain influenced are respectively, Pinus massoniana Lamb.: 0.49,0.34,0.25; Schima superba Gardn. et champ: 0.70,0.34,0.32; Cyclobalanopsis glauca (Thunberg) oersted: 0.64,0.23,0.21; Acid rain also affected the dry weight remaining of leaf litter for three typical tree species. Comparing with control (pH56), the moderate acid rain (pH4.0) and severe acid rain (pH2.5) impacted the decomposition about 95% completely time of leaf litter, the results indicated: Pinus massoniana Lamb. postponed are 2.697a, 5.869a; Schima superba Gardn.et Champ are 4.531a, 5.082 a; Cyclobalanopsis glauca (Thunberg) Oersted are 8.344a, 9.584 a.