Abstract: The effects of rainfall on the nutrient leaching and the seasonal variations of nutrients in rainfall, throughfall and stemflow in the moist evergreen broadleaved forest at the Ailao Mountain in Yunnan Province were analyzed and discussed based on the data collected during 1990～1992. The results show that the concentrations of N, P, K,Ca and Mg were different among rainfall ,throughfall and stemflow. The concentration and input of nutrients were higher in the rainy than in the dry season. The concentration of nutrients in stemflow was higher than that in throughfall which in turn was higher that in rainfall. The contributions to the nutrient input of the stands of the rainfall and the leaching from the trees were also discussed.