Since June 2014 the improvement on the supply side has been the main driving factor of the plunge of oil price. Based on the history of oil price movement after 1970s，we find that the supply-side increases will restrain the oil price from rising in the long-run. We estimate that the average level of oil price will be around 50-65 USD/barrel from 2015 to 2016，and the new normal level of oil price will be close to the marginal producing cost. Geopolitical conflicts may trigger the oil price rebound，but won’t change the long-term trend of oil price. The oil price fall will benefit the global and China’s economic growth. Monetary policy should not overreact to the deflation incurred by oil price changes. The oil price decline provides opportunities for alleviating debt load，and reforming fiscal policies and foreign reserves management policies. China should take part in the multilateral and bilateral political negotiation more actively and help to ease the geopolitical conflicts in oil-producing countries.