ion: In average, more than 70 percent of the freshwater is used for agricultural demands. Especially in arid and semi-arid zones, groundwater is the most important water source for agricultural demand. On the other hand, nitrate is an important pollutant source for groundwater resources. The presence of nitrate pollution is due to human activities such as the excessive use of chemical and natural fertilizers, the lack of wastewater treatment systems in urban and rural areas and the inadequate disposal of industrial and animal waste. In recent decades, the use of nitrogen fertilizers have been expanding regardless of their side effects on soil and environment. The purpose of this thesis is quantitative and qualitative modeling of Booein-Miandasht aquifer located upstream of Zayandehrood Basin which according to existing evidences, has been contaminated by nitrate. At the first step, groundwater quality and quantity modeling was down by MODFLOW, and MT3D. Then a surrogate model by using artificial neural network (ANN) built as quality-quantity simulation model. So, an optimization model was presented with two objectives: first objective is minimizing the concentration of nitrate in groundwater by reduction of fertilizer use, implementation of sewage system and wastewater treatment plant and changing the type of cultivation in agricultural zones, which consequently reduces the amount of fertilizer; and the second objective is maximizing the net benefit of farmers. For this two-objective optimization problem, the Booein-Mindasht aquifer was divided into three regions and the results of the model were obtained separately for each zones. In all three zones, farmers' net benefit is rising during the planning period. NSGA II used for getting the optimum solutions and extraction of Pareto front. Three water years (1391-1394) used for getting the best solutions. The results show that the highest concentration of nitrate occurred in the first zone, which contributed 36.7% to the contaminated scenarios. Based on the results in this region, we must reduce the concentration of nitrate by treatment of wastewater (15% reduction), and reducing fertilizer for agricultural lands (9%). In the second zone, the concentration of nitrate must be reduce by treating wastewater (12%) and reducing fertilizer for agricultural lands (6%), that causes 20.45% reducing of contamination in this region. Finally, the third region of aquifer has the lowest nitrate contamination and the highest crop area; according to the optimal results obtained, we must reduce the concentration of nitrate (9%) by treatment of wastewater and reducing fertilizer for agricultural lands (7%), for getting standard concentration of nitrate in the aquifer. Keywords: Quantitative and Qualitative Modeling of Water, Booein-Miandasht Aquifer, Nitrate Pollution, Simulation-Optimization Model, Artificial Neural Network, Optimization by NSGA II.