Populus euphratica Oliv. is a dioecious tree species for windbreak, sand fixation and soil and water conservation in desert riparian forest. In this study, male and female Populus euphratica plants with different diameter classes (8, 12, 16, 20 cm) were used as the research objects. Through analysis the contents and growth relationship of stoichiometric elements (C, N, P, K) in stems and leaves of the current year, the stoichiometric changes of different classes with developmental stages and the sex differences in allometric growth relationships were discussed. The results showed that: (1) the C content in the leaves of male and female plants of P. euphratica showed that the largediameter class (20 cm) was significantly higher than that of the small diameter class (8 cm), and the N content of leaves increased significantly with the increase of diameter class; Stem and leaf stoichiometry of male and female plants generally increased with the increase of diameter class, and C and N contents were significantly positively correlated with diameter class; With the increase of diameter class, the P content in leaves of female plants showed a downward trend, which was significantly negatively correlated with diameter class, while the P and K contents in stems of male and female plants showed an upward trend, and there was a significant positive correlation with diameter class. (2) The N content of the leaves of each diameter class and the P content of the 8, 12, and 20 cm diameter classes of the female plants were significantly higher than those of the male plants, and the C content of the current year stems of the 8, 16 and 20 diameter classes and the N and P contents of the stems of the 20 cm diameter classes were significantly higher than that of the corresponding male plants. (3) The slope indexes of C and N in the leaves of female plants are the largest in the 20 cm diameters class, while the slope indexes of male plants are the largest in the 12 cm diameters class. The changes of N and P in male and female plants are relatively stable in each development stage. At the same C content, the male stem can obtain more N content, and the female stem can obtain more P element under the same N. The research found that there are significant gender differences in the stoichiometric content and allometric growth relationship characteristics of stems and leaves between male and female Populus euphratica at different development stages. The mature female leaves need more stoichiometric characteristic content to meet the reproductive needs, which generally reflects the nutrient distribution strategy of their own growth and environmental adaptation.