The invention relates to a multifunctional alcohol fuel additive, aiming at resolving such technical problems existing in prior alcohol fuel as the mutual solubility, the power performance and the stability are poor, cleaning degrees of oil products and fuel oil system are poor and the corrosion and the air resistance of methanol gasoline can not be effectively handled. The additive comprises following components in portion by volume: 50 to 60 portions of cosolvent, 5 to 10 portions of corrosion inhibitor, 0 to 30 portions of detergent dispersant, 0 to 10 portions of rubber plasticizer and 0 to 15 portions of vapor pressure inhibitor. The additive has the advantages of high octane value, strong power performance, good stability, desirable mutual solubility, environmental protection and energy conservation, and can effectively inhibit metallic corrosion, improve the cleanness of oil products and resolve the problems of air resistance.