Over half the worlds population now live in urban areas and because of this the urban forest plays a crucial role in the ecology of human habitats. On the other hand, one of the most limiting factor of landscapes development is securement of water for plants. Deficit irrigation is a desirable method for saving water use in water deficit conditions and ultimately reducing necessary cost of water securement to landscape plants. Also may inoculation of plants’ root with mycorrhizal fungus can to used as method to reduce water need of plants. Because of the importance of trees or that they are intrinsically linked to our health and well-being and as Elm ( Ulmus carpinifolia Borkh.) is one of the important trees planted in urban landscapes of Iran, The current investigation was conducted to evaluate the effect of inoculation of plants with mycorrhizal fungus on response of elm trees in different applicable water levels (securement the 50 and 100% of water need). A factorial experiment was condocted based on the completely randomized design with 5 replicates. The results of the experiment showed that drought stress had negative and significant effect on most growth chracteristic of Elm trees. Inocultion of plants with mycorrhizal fungus significantly increased majority of morfological growth parameters including fresh and dry weights and height and diameter of elm trees. Also, the content of relative water was increased with application of mycorrhizal fungus. On the other hand, proline concentration in leaves in deficit irrigation conditions was increased and inocultion of plants with mycorrhizal fungus significantly decreased proline concentration in plant leaves . Concentration of phosphorus and nitrogen in inoculated plants significantly increased as compared to non-inoculated plants. inoculation of elm trees with mycorrhizal fungus resulted singnificant increase in most growth and physiological parameters such, soluble sugar, chlorophyll content, photosythetic indices and activity of some antioxidant enzyme such as catalase (CAT) and ascorbate peroxidase(APX) as compared to control. To sum up, the obtained resutls revealed that inocultion of plants with mycorrhizal fungus, improved plants growth under stress conditions through its positive influence on nutrient uptake, chlorophyll content and subsequently increase in photosynthesis. The results suggest a promising mehod to preserve elm trees under difficit irrigation when the roots are inoculated by mycorhizal fungi. Keyword: Landscape, Irrigation level, Elm tree, Mycorrhizal, Chlorophyll, Nutrient, Enzyme