The growth of Daphniphyllum macropodum at Mt. Naejang National Park(Naejang temple area) was investigated in connection with the climatic factors by the use of tree-ring analysis. A pair of cores was extracted from each of 18 trees in the D. macropodum community area near Younjabong for the analysis. The period of mater chronology based upon D. macropodum covers from 1915 to 1998. The growth rates of D. macropodum were very poor in the years 1920, 1932, 1934, 1937, 1942, 1946, 1964, 1969 and 1985, respectively. Response function was employed to understand the relationship between the growth of D. macropodum and climatic factors. The response function of the growth rates of D. macropodum indicated significant negative correlation with the precipitation of August and September. Poor growth of D. macropodum during the August and September nay be due to the frequent rain periods during the summer The heavy rain during the summer seems to decrease the solar radiation, which eventually caused the decrease of photosynthesis capacity. In conclusion, we hypothesize that the decrease of the photosynthesis rates during the rainy summer seasons may cause the slower growth of D. macropodum.