Abstract: In order to find out if the height/basal diameters dynamic growth of seedling Pinus Yunnanensis changes with the temperature in a certain period,a study was carried out in one-year old P.yunnanensis and the data was collected and analyzed.The relation was summarized by regression analysis and segmentation method.The results showed that:① The relationship between net growth and the indices of temperature accords with quadratic curves,temperature within a certain range facilitates the growth of height and diameter,while deviation from the optimum temperature inhibits the growth to some extent;② The optimum temperature,≥10 ℃ accumulated temperature,minimum temperature,maximum temperature for height growth are 23.05,237.94,18.35,26.07 ℃ respectively,and for diameter growth they are 16.59,641.24,10.42,21.92 ℃;③ Different temperature affects the seedling growth in different ways.The height growth is inhibited by the extreme heat before the end of September and the extreme low temperature after that.The basal diameter growth is inhibited by the extreme heat before mid-late November and the extreme low temperature after that;④ The optimum temperature for the height growth appears 1—2 months earlier than that of the diameter growth.Therefore,allometry is shown during the growth of the seedlings,as the peak for the diameter growth occurs after the peak for the height growth.