The invention discloses a composite fuel oil. The composite fuel oil is prepared from, by weight, 0.04 to 0.07 part of ferrocene, 2-4 parts of isopropyl nitrate, 0.4-0.6 part of ethylene glycol monomethyl ether, 0.04-0.05 part of succinimide, 6-9 parts of diisopropylether, 8-12 parts of ethyl alcohol, 7-9 parts of iso-butane, 10-12 parts of glycerinum, 16-19 parts of methyl alcohol, 0.6-0.9 part of polyether amine, 2-4 parts of acetone, 3-5 parts of hydroquinone and 4-6 parts of methyl tertiary butyl ether. The composite fuel oil can replace petroleum fuel and is high in combustion efficiency,strong in combustion power performance, less harmful gas is exhausted, carbon deposition in an engine can be avoided, the raw materials are easy to obtain, and the production cost can be reduced.