This study was carried out as apartial study to search the mechanisms of salt tolerance in date palm tree (Hillawi) by the study of the effect of salty irrigation water by NaCl (0, 6, 12, 18, 24) dS/m on leave area, water potential and the decrease percentage in water saturation of leaves, Moreover, to study of some histological characteristics (width of cuticle, epidermis, mysophyll, and the diameter of each cell in this tissue). The results showed that the salinity causes a decrease in both the leave area and water potential, where the increase in salinity lead to a more decrease in water saturation of leaves. The histological characteristic showed a decrease in length, width of epidermis and mesophyll with increased salinity but the cuticle is increased with elevated salinity.