Abstarct: This study explained the causal relations of iran's comprehensive energy system by system dynamics approach. The purpose of this research is to find models and the factors influencing in this section to making decision by positive features of system dynamics approach for a more comprehensive vision in the energy sector. The community in this study including nonrenewable energy, oil and gas and renewable energy including electricity, solar energy, hydropower and wind, respectively. The data used in this study were collected and the corresponding graphs were expressed 1991-2013. By review the reference energy models, previous researches and studies, total of 88 variables related to interactions existing between energy variables and its sub-sectors order to objectives of this research were estimated. The effects of these variables on each other were drawn in the software vensim by the causal relationships in four separate diagrams including "supply and demand, energy security, investment in fossil energy and renewable energy". According to the results of the study low energy price has created the phenomena such as encouraging the use of inefficient and consuming resources, the use of surplus energy incom, benefiting the wealthy interests, causing adverse effects on the environment, reduce the development of renewable alternative energies, lack of energy storage and adequate funding for production to adapt to the growing demand and import gasoline because of high consumption. In this study, the use of leverage equilibrium price as a way of preventing early completion of reserves and maintain them for more years are presented. By liberalization of energy prices demand adjustment occurs and its profits leads to profitability energy sector, providing resources and funds needed to r&d investment in this sector to develop energy-saving activities, increase reserves and increase export revenues will be available for export. By investing in the energy sector, production capacity of resources available increased and can be added to the quantity supplied. Of course, with production of resources they will be decreased, and need to inject oil and gas and other methods of eor occurs.