The invention provides an anti-corrosion processing method of the casing of the fuel oil filter, which adopts a separation method to enable the metal structure of the casing of the fuel oil filter not to be corroded to prolong the service life of materials. The technology of the inner wall of the casing of the fuel oil filter adopts one paint-one bake craft. The adopted anti-corrosive paint is composed of a epoxy phenol aldehyde finish and a epoxy phenol aldehyde finish thinner, while in use, the two finishes are stirred uniformly by the proportion, and then are painted on the inner wall and the bottom part of the casing, after painting, baking in the furnace. The invention has the advantages of simple technology, convenient operation, solving the problem of oil linkage of the casing of the fuel oil filter caused by long-time corrosion of the diesel fuel medium, improving the anti-corrosion performance of the casing, and obvious economic benefit and huge social benefits.