Abstarct: Hamedan- bahar Plain is one of the most important plains of Hamedan province in terms of agriculture and water quality. The occurrence of multiple droughts and excessive utilization of groundwater resources in the Hamedan- bahar plain are considered as the main causes of groundwater abatement. First, a conceptual model of groundwater was prepared using all data and information. In this research, simulation of groundwater table of Hamedan plain - spring in a stable and unstable state using GMS7.1 model and MODFLOW computer code by finite difference method. During the simulation, in order to calibrate the model in a sustainable condition, the groundwater level of April 2005 was used and in order to calibrate the model in non-residual conditions, water level statistics for the years 2005 to 2010 were used. The calibration of the model was carried out in both situations using the PEST code. Also, to assess the accuracy of the model, water level statistics were used from 2010 to 2014, and after the results of the verification confirmed the conformance of the model to the aquifer's natural conditions, a mathematical model was constructed to achieve the objective of the study. According to the data of 27 observation wells and comparison of computational water level of model and observation, parameters such as hydraulic conductivity coefficient in steady state and aquifer saving in unsteady condition, which have more uncertainty, were optimized. The model simulated water level is close to the observation water surface and the average root mean square error for all plain piezometers in this 5 year period is 1.56. In order to predict the level of groundwater in the years to come, three drainage scenarios of 2 times, a drought of half the rainfall and the current trend for the plain are defined. The results showed that during the period from September 2016 to September 2021, if the current rainfall continues, the groundwater level will decrease by 3 meters. baxsed on this amount, the total area of the aqueduct of Hamedan- bahar plain and average storage factor 0.05 will leave about 77 million cubic meters of water from the plain.