Abstract: The relationships between tree ecophysiological activity and underground water table need to be studied because a huge number of trees died in arid and semi-arid area during recent years for the decreasing water table due to increasing water consumption. In this study, the water table was represented by the distance from soil surface to water surface. Study on the effect of water tables on the ecophysiological characteristics and growth of Ulmus pumila saplings was conducted by a short-term experiment. Saplings at water tables of -5 (under water), 3, 9, 15 and 22 cm were abbreviated as U-5, U3, U9, U15 and U22. Present results indicated that water table did affect the ecophysiological and growth response of U. pumila. All U-5 died after one week. U9 and U15 had higher net photosynthesis rates than those of U3 and U22. The diurnal mean transpiration rate of U3 was significantly lower than that of U9, U15 and U22, respectively. The diurnal mean stomatal resistance of U3 was significantly higher than that of U9, U15 and U22, respectively. U22 had the highest increment in main root length and there was good correlation between water level and main root length. U15 had the highest increment in stem height. Maintaining proper water table would result in higher net photosynthesis, water use efficiency, plant height and root length, but relative lower transpiration rate for U. pumila saplings. These results would have implications for water management at arid and semi-arid area for vegetation survival and regeneration. Seedlings and saplings should not be submerged for a long time during irrigating. Ecophysiological measurements can indicate the underground water table. Maintaining proper underground water table at arid and semi-arid area would be helpful to the growth of plant species and vegetation.