To understand the variations of nutrients and stoichiometric ratios in Populus ×xiaozhuanica cv. Zhangwu seedlings under drought stress, we grew the seedlings in pots under a condition of continuous natural drought. Carbon (C), nitrogen (N), phosphorus (P), and potassium (K) contents in different organs (leaf, stem, root) were measured at 0, 6, 12, 18 and 24 days after drought, and the correlations of elements among organs were analyzed. Results showed that N and K contents and C∶P and N∶P decreased but P content and C∶N and C∶K increased in all organs after 6 days of the drought. N content and C∶P and N∶P increased but P content decreased in all organs when the drought lasted from the 6th day to the 12th day. Root C content, C∶N, C∶P and C∶K showed downward trends when the drought lasted from the 12th day to the 24th day. Under continuous drought treatment, there were significant positive correlations in N or P content among leaves, stems, and roots, as well as C content between leaves and stems, and K content between leaves and roots. P.× xiaozhuanica cv. Zhangwu seedlings could adjust the stoichiometry of C, N, P, and K in various organs to adapt to the gradually intensified drought stress. First, C supply for roots increased, K transferred from stems to leaves and roots, and N content in each organ increased to resist drought stress. Finally, C supply for roots decreased, N consumption increased, and P and K accumulated in the seedlings.