Abstarct: Behabad basin in Yazd province, which is a part of great basin of Kavir-Loot, encompasses an unconfined aquifer with an area of about 366 Km^2. The quantitative and qualitative assessments of the aquifer have been carried out in this study. Groundwater resources in Behabad plain are mainly used in agricultural and industrial sectors. Which has caused high annual drawdown in the aquifer. Concentration of the pumping wells specially industrial wells, in the central part of the aquifer has created a depression in water table in which, flow lines are focused, resulting in different patterns in flow pattern in northern and southern parts of aquifer. Representative hydrograph of the aquifer shows the average annual declines are approximately 60 and 40 cm for southern and northern parts, respectively. baxsed on water balance of Behabad aquifer in water-year 1389-90, total inflows are 20.8 and 6.8 MCM, less than the total outflows of about 32.9 and 8.5 MCM in southern and northern parts, respectively. Safe yield was calculated at 22.3 and 3.7 MCM for these regions. Total discharge from the aquifer was more than the natural recharge and safe yield, causing decrease in storage and negative balance of the aquifer followed by decline in water table. Management of various uses in both agricultural and industrial sectors are necessary to attain a safe yield in the region. Evaluation of the quality of the aquifer indicate that salinity and electric conductivity increase with depth, so the quality of discharge water is being worsen as the water level is declined. Dominant water- type of Behabad aquifer is Na-Cl. The average electrical conductivity at aquifer is about 4505 µmohs/Cm and the increasing trend of EC represent quality degredation of the aquifer with time.