The invention provides a water-soluble antirust agent. The water-soluble antirust agent is prepared from fatty acid, specific amine, an additive, ethyl alcohol and water. The mass ratio of the fatty acid to the alcohol amine to the additive to the ethyl alcohol to the water is (2-3):(1-15):(5-10):(10-15):(80-100). The fatty acid is selected from one or more of oxalic acid, valeric acid, naphthenic acid, citric acid, benzoic acid, lauric acid, adipic acid, oleic acid and sebacic acid, the apecific amine is selected from one or more of octanoic acid dicyclohexylamine, triethanolamine, diethanol amine and ethanol amine, and the additive is an antioxidant. The antirust valid period of the water-soluble antirust agent is long and can reach 3-6 months; an antirust film is thin and is only tens of microns thick, a follow-up process cannot be influenced even though the antirust film is not removed, and the film can be removed with warm water due to the good film removability of the water-soluble antirust agent; and the water-soluble antirust agent is low in production cost, free of foreign smells and beneficial to environmental protection.