Abstract: The potential effects of future rainfall change on hydraulic and growth characteristics of seedlings of Sabina vulgaris, a dominant evergreen shrub of the semi-arid Mu Us sandy desert were examined in a controlled experiment simulating rainfall change conducted at the Ordos Grassland Ecological Station. Water saturated deficit (WSD) and tissue density (TD) decreased with increasing of soil water significantly, while the water loss coefficient (k) increased. This indicates that drought-resistance and water-holding ability of seedlings decreases with increasing simulated rainfall. The simulated water gradient had no significant effects on the ratio of branch to stem area, while a significant influence on the ratios of leaf mass to stem area and leaf mass to branch area was found, suggesting that the potential effects of water supply on seedlings decreases with increasing water availability. Biomass allocation was also significantly influenced by the water gradient; In contrast both morphology and the canopy productivity index showed no significant response to the water gradient. Changes in biomass increment, plant height, and basal diameter with water gradient reflected the slow-growing attributes of the seedlings. The sensitivity of roots to water change was higher than that of leaves and stems. The below-ground biomass allocation increased with increasing of water availability, implying that the seedlings may adapt to water stress through more economical use of water resource in natural habitats.