Economic order quantity is a model used to calculate the optimal order for an item based on the cost of ordering, buying, storing and shortage. Therefore, we propose dynamic EOQ consisting of the variables, which have interrelation, delay factor, feedback loop, and as a closed system in the system dynamics model. Through this model, we can do various scenario to get the minimum total cost associated with policies that can be done on variables controlled (exogenous variable of a dynamic system). However, we only limit the two scenarios to get the minimum total cost, which is the inventory target and delay of replenishment. Based on two scenarios, this article can show the simulation output as the graph of variables (the dynamic behavior) and clarified by statistical data (maximal value, minimal value, total, deviation standard, and average) that can be used to choose the policy to achieve the minimum total cost of dynamic EOQ. In this article, scenario increasing inventory target results in the decrease of total cost less than the decreasing delay of replenishment.