Irregular increase of money supply in recent years has caused many economic problems such as intensifying inflation and degrading industrial sector. To avoid this increasing scientific improvisations are needed. In this way the aim of this paper is to develop a dynamic model for simulate and study the future trend of money supply changes. To achieve this goal some part of the monetary section of Iran economy has been modeled using system dynamics and soft computing. Soft computing method which is used in the model includes artificial neural networks and genetic algorithm. After validating the model some scenarios have been designed and simulated in order to study the future trend of money supply. Results of running the model showed that in conditions which oil income increases as previous historical trend, taxing rate is about 0.06 and formal exchange rate is lower than 30000 Rials, money supply will almost diminish to 2 thousand billion Rials. The conclusions of this paper can be used in central bank policy making, budget deficit regulations, price level controls and many other economic studies.