Abstract: This paper studied the community characteristics of two sandfixing plants (Artemisia ordosica and Caragana korshinskii) under different configuration modes (1 m×1 m and 2 m×2 m) in the Shapotou region of Northwest China as well as the water relation, gas exchange, and their adjustment mechanisms of the plants under natural and artificial precipitation conditions. With the variation of soil water content, the physiological water consumption and growth characteristics of A. ordosica differed from those of C. korshinskii. A. ordosica presented obvious fluctuation in the stomatal conductance, water potential, transpiration rate, photosynthetic rate, and rapid growth, and had higher water consumption than C. korshinskii. However, the variations of the abovementioned indices of C. korshinskii were relatively slow and more constant. The C. korshinskii had a lower photosynthetic rate but a very high accumulated biomass over years than A. ordosica. The response procedures and adjustment mechanisms of the two plants under water stress differed, with a water-conserving mechanism for A. ordosica and a watersaving mechanism for C. korshinskii. In extremely drought years, the C. korshinskii had stronger capabilities of water-saving and stress tolerance than A. ordosica. It was suggested that the selection of sandfixing plants should have a view to the benefits in water saving and sand fixation, and also, to the stability of sand-fixing forest.