Abstract: In order to attain a better understanding of the nutrient dynamics in Populus tomentosa, contents of N, P, K, Ca, Mg, Fe, Mn, Cu and Zn were determined in foliage in every spring, summer and autumn from 2 to 4yearold poplar plantation. And statistics were analyzed in the way of repeated measures by SPSS 17.0. The results showed that seasonal dynamics of foliar nutrient contents varied significantly. In addition, foliar P, Ca, Mg, Fe, Mn contents and N/P ratios changed remarkably with the age of the plantations. At the same time, the seasonal trends of P, K, Mn contents and N/P ratios obeyed linear models, while those of N, Ca, Mg, Fe, Cu and Zn contents followed quadratic models. Moreover, according to the tests of betweensubject effects, all nutrient elements contents varied significantly with the plantations ages. But in terms of the clone factor, the Mg and Mn contents varied significantly.