The invention relates to strippable and easily-recoverable hard-film rust preventive oil. The hard-film rust preventive oil contains a main film forming agent, an auxiliary film forming agent, a rust preventer, a plasticizer, an antioxidant, other additives and a solvent and is uniform transparent liquid which is prepared through proportionally mixing all the ingredients. According to the hard-film rust preventive oil, the main film forming agent is selected from natural products such as cellulose, agarose and chitosan, and derivatives thereof, and other ingredients, i.e., alkali metal or alkaline-earth metal petroleum sulfonate with relatively good rust resistance, amides with better film forming or supplementary film forming property, carboxylic acids with relatively high polarity and relatively high adsorptivity, esters which give attention to product rust prevention and product stability improvement, and naphthenates which give attention to rust prevention and drying assisting performance are selected, so that the product is relatively good in film forming property and toughness and is applicable to operation of different oil impregnation processes such as dip-coating, brush-coating and spray-coating; during removal, the common solvent cleaning process can be changed into a manual stripping process, and the product obtained through stripping can be recovered and then be recycled as a new raw material, so that the pollution discharge of downstream enterprises is lowered.