Leaf functional traits are closely related to plant growth strategy and resource utilization efficiency. The knowledge of how leaf functional traits vary along a climatic gradient is important to understand the adaptation mechanisms of plant to climate change. Nitraria tangutorum is a shrub widely distributed in desert areas of the northwest China and plays important roles in reducing wind and stabilizing sands in these regions. In this study, specific leaf area (SLA), mass- and area-based leaf nitrogen concentration (N_mass, N_area), leaf construction cost per unit mass and area (CC_mass, CC_area) of N. tangutorum were measured along the climatic gradient. Our objective was to investigate how leaf functional traits and their relationships within species of N. tangutorum would change along the climatic gradient, which is crucial for understanding the response of arid plants to climate change and providing the scientific basis for desertification control. The results showed that except for CC_area, the leaf functional traits of N. tangutorum differed significantly along the climatic gradient. Partial correlation analysis of multiple linear regressions between leaf functional traits and climatic and soil variables indicated that annual mean temperature was the main factor that determined the variation of SLA of N. tangutorum, and SLA increased with the increased temperature. Both annual precipitation and annual mean temperature had significant effects on N_mass, N_area and CC_mass of N. tangutorum, N_mass and N_area decreased with the increased precipitation and temperature, while CC_mass showed an increasing trend. Neither annual mean temperature nor annual precipitation had significant effect on CC_area of N. tangutorum. Along the climatic gradient, the individual SLA-N_mass slopes within species of N. tangutorum did not differ significantly among the study sites. However, there were significant differences in the SLA-N_mass slope elevation between the low annual mean temperature, precipitation site and the high annual mean temperature or high annual precipitation sites. In general, the low annual mean temperature and annual precipitation together significantly increased the elevation of the SLA-N_mass relationship. There were also similar shifts in the positive relationships of CC_mass-N_mass and CC_area-N_area within species of N. tangutorum, i.e. the slopes in these leaf trait relationships held stable along the climatic gradient, while only their elevations varied significantly. In conclusion, our results indicated that along the climatic gradient, plants from areas with low annual mean temperature and annual precipitation had higher N_mass and N_area under given SLA, CC_mass and CC_area, which suggested N. tangutorum adapted to the climate changes through regulating various leaf functional traits and forming the optimum functional combinations of the traits.