In recent months, the world oil market has shown an abnormal behavior as compared with past few years, with the most relevant feature of unpredicted prices. We primarily aim to design stockpile policy to deal with oil insecurity issue that do exist and will likely intensify in the future. We concentrate on the demand side on the ground of our observation of its significant impacts on oil price, develop a stochastic multiperiod model and employ the recursive method to look for the optimal path of stockpile size indicated by the optimized dynamics of acquisition. We, with the objective of minimizing potential oil insecurity costs over a long time, figure out that the optimal stockpile policy is that the acquisition rate is 3.25 million barrels per day in the initial year, rises and reaches the peak 8.73 million barrels per day later and then declines gradually.