To understand ecophysiological adaptation of Sabina vulgaris under drought stress，the ecophysiological characteristics of this species were studied in the field and laboratory．Investigation in the field was done at Mowusu Sand Land in Inner Mongolia of China，and laboratory experiment was done at Okayama University of Japan．The lab experiment consisted of three treatments：control with 0 MPa，light drought stress with-0．1 MPa，and strong drought stress with-0．3 MPa in gravel culture box．The field and laboratory experiment results show that the efficiency of water utility is increased while increasing drought stress by the following aspect：（1）In growth．It increases the survival of individual by withering away the lower branches and leaves of the individual plant and increases the survival of population by thinning．（2）In gas exchange．The stomas closes，and all of the gas exchange rate，photosynthetic rate and transpiration rate decrease．The ratio of photosynthesis and water utility is increased under drought stress，since transpiration was inhibited more strongly than photosynthesis．（3）In water absorption and protection．The plant increases water absorption and dehydration capability by adjusting osmotic openings and decreasing the elasticity of cell walls；the adaptability to drought stress is also strengthened by increasing the density of stoma，increasing the sensitivity of stoma adjustment to drought stress，and increasing the thickness of the cuticular layer and reducing transpiration．