The invention relates to a clean fuel additive and fuel oil using the same. The additive comprises C1-C4 fatty alcohol and a polymer, wherein the C1-C4 fatty alcohol is one or more of methanol, ethanol or isopropyl alcohol; and the fuel oil comprises the additive and internal combustion engine fuel oil. By using the fuel oil, the working time of an engine can be prolonged, the exhaust emission is reduced and the combustion intensity is improved.