The invention relates to an additive composition for producing emulsified oil, a preparation method of the additive composition and an application of the additive composition. The additive composition is prepared by the following components in parts by weight: 0-15 parts of base oil, 0-10 parts of grease, 5-10 parts of higher aliphatic acid, 5-15 parts of alkylol amine, 15-35 parts of sodium alkane sulfoate, 10-25 parts of dehydration sorbitol single oleate, 2-15 parts of fatty alcohol-polyoxyethylene ether, 1-10 parts of coconut oil fatty acid diethanolamide, 1-10 parts of polyoxyethylene dehydration sorbitol single oleate, 0-0.6 parts of copper alloy corrosion inhibitor, 1-7 parts of antiseptic bacteriacide and 1-8 parts of water. The additive composition is good in stability, easy to keep and transport, strong in emulsifying capacity and high in emulsifying efficiency. Prepared emulsified oil is good in hard water resistance and good in foam restraining performance.