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Physiological characteristics of natural hillocks of Tamarix taklamakanensis growing under different groundwater conditions were studied in the hinterland of Taklimakan Desert using pressure-volume (PV) curves and leaf gas exchange measurements in 2011. The water potential decreased as groundwater salinity increased; however, the groundwater depth had no significant effect on the plant water potential. Transpiration rate (Tr) and stomatal conductance (g) decreased with the depth and the salinity of the groundwater increased. In July, the diurnal transpiration rate and stomatal conductance showed double-peaked curves, with peaks of stomatal conductance coinciding with peaks in transpiration rate. In September, the diurnal transpiration rate was a single-peaked curve in samples from site A, a double-peaked curve for samples from site B and a delayed single peak of transpiration rate compared to stomatal conductance in samples from site C. Osmotic potential (psi(tlp)) and relative water content (RWCtlp) at zero turgor were reduced as the salinity of the groundwater decreased, while the apoplastic water content (AWC) decreased with increasing salinity. T. taklamakanensis apparently adapts to the special environment of the desert hinterland by maintaining a high water content and high transpiration rate.