: Due to population growth and increase the need for water in the field of agriculture, industrial and urban, supply water requirements, is one of the major concerns of senior management in the field of water resources in many countries including our country. One of the fundamental solutions for supply water needs is optimal conjunctive use of surface water and groundwater resources. To do this simulation-optimization method is used. In this study, optimum utilization of surface and groundwater resources in the Najaf Abad study area in Zayandehrud basin has been studied. Given that the agricultural sector in the area is the major consumer of surface water, transmitted Nekuabad irrigation networks (both right and left) and groundwater, management model to determine the optimal allocation of surface water and groundwater resources has been discussed at monthly time steps. The management employed the combination of data-driven simulation model of neural network and harmony search optimization algorithm. Thus, in each iteration of the optimization algorithm, a simulation model for the variation in the ground water levelwas shown. Management model was run under different scenarios and using the optimization algorithm, uptake of surface and ground water resources was achieved. The results show that most of the region's water supply needs are suplied in Nekvabad right side, but in the left sideofNekvabad,due to high water requirements,there is no possibility of water supply in most conditions. Key Words: Conjuctive Management, Surface Water, Groundwater, Harmony Search Algorithm.