An optimum government oil stockpile ratio is found by pursing the maximum net benefit of whole economy. Whether the government oil stockpile is necessary or not depends on the relative benefit and cost of government and private firms. Government should keep some oil stockpile if more net benefit is created by government oil stockpile. While the optimum government oil stockpile ratio would vary from economy movement, it is suggested that a range of government oil stockpile ratio should be considered for replacing current fixed one. Moreover, a more flexible oil stockpile mechanism is contended for enhancing total net benefit of whole economy.