Larrea tridentata is a xerophytic evergreen shrub, dominant in arid regions of the southwestern United States. The success of this desert shrub (creosote bush) has been largely attributed to its capacity for maintaining turgor pressure and stomatal control of photosynthesis under drought stress. However, the drought-resistance characteristics of plants are very complex. In addition to hereditary factors, environmental conditions may have strong impacts on the physiological performance of desert shrub seedlings, which may result in different performance of its drought-resistance capability. To study the drought resistance capability of L. tridentata, which was introduced to China from the United States, water parameters of the branches were determined in this study.The water potential of 1-year-old small branches of creosote bush was measured using the pressure chamber method. Four soil water potential levels were considered, namely, -0.021, -0.121, -0.698 and -0.968 MPa. Pressure-volume curves(PV curves) were generated over a wide range of water potentials to determine drought-resistance characteristics of the species. We obtained Ψ_π¹⁰⁰ (the largest osmotic potential under the saturation moisture content), Ψ_π⁰ (osmotic potential when the turgor pressure value is zero), ε_max (elasticity module in the largest volume), V_s (free water content), V_a (bonded water content), RWC⁰ (relative water content when turgor is zero), ROWC⁰ (relative content of the penetrated water when turgor is zero), and Ψ_p (turgor pressure) from the PV curves. The results show that the diurnal transformation curve of water potential had two peaks when soil water content was sufficient, and the character diminished with decreasing soil water content. The relationship model between soil water potential and Ψ_p is y=1.0541x^0.5033. It is concluded that the branches of L. tridentata can hold high water potential and its dehydration tolerance is strong, similar to that of conifers. Under drought conditions, L. tridentata took on an ability of osmotic adjustment and maintained Ψ_p, mainly by improving cell-wall elasticity and retaining a higher proportion of water bound. Its capacity of sarcode dehydration tolerance is strong. With increasing drought stress, the capacity of the L. tridentata to maintain turgor pressure declined, whereas its capacity to tolerate dehydration increased. Moreover, we used a membership function to operationalize data from the PV curve into quantitative indices, obtaining fuzzy values of 0.25, 0.17, 0.933 and 0.657 under four soil water potential conditions. Overall, the drought-resistance ability of L. tridentata was maintained and strengthened as soil moisture decreased. The drought model suggests that L. tridentata belongs to high water potential and dehydration-delaying species. Its drought-enduring mechanism operates mainly by restricting moisture loss and adopting available moisture to maintain higher water potential, combined with enduring dehydration with low water potential. That is, the protoplasm and main organs of the L. tridentata are unharmed or only slightly harmed under serious drought conditions, because of its cell-wall elasticity. These conclusions coincide with results obtained in the United States, and confirm that L. tridentata has maintained good drought resistance capacity after cultivation in China.