Abstarct: Abstract This research is entixtled "Petrol Consumption Dynamics in Iran" and aims to analyze the dynamic demand of this fuel during 1979 to 2021 in the country. The research method is dynamic systems approach. In this method, the dynamic and complex behavior among variables and the type of their effect on each other is investigated by using Causal-Loop diagrams and Stock-Flow diagrams. In the dynamic model, the effect of population variables, trips, the number of petrol cars, the number of dual-fuel cars, the number of CNG stations and the consumer price index (CPI) are included. In order to validate the research and sensitivity analysis, gasoline consumption is predicted baxsed on the dynamic model for the period of 2006 to 2021 and for the period of 2022 to 2031 under the basic model and three different scenarios. The first scenario examines the change in the predicted values of the baxse model if the number of dual-fuel vehicles increases and we change the coefficient in the dynamic model from 0.1729 to 0.3500. In the second scenario, by changing the coefficient of the number of CNG stations from 0.1870 to 0.2200, the effect of easy access to CNG fuel on gasoline consumption has been investigated. The third scenario also shows the effect of the simultaneous change of the previous two scenarios. The results show that all three policies help to reduce gasoline consumption, but the policy of increasing the number of dual-fuel vehicles in the first scenario has a greater effect than the policy of increasing the number of CNG stations (second scenario) in reducing gasoline consumption.