The utility model discloses a portable combination formula oil strain device, including preliminary filter, I grade of filter core, II grades of filter cores, III grades of filter cores of a plurality of, manometer, miniature oil pump, oil feed butt joint tube heads, the butt joint tube head produces oil, preliminary filter continuous to taking over with the oil feed, preliminary filter, I grade of filter core, II grades of filter cores, III grades of filter cores of a plurality of are arranged in proper order, are provided with the manometer on III grades of final filter cores, are provided with miniature oil pump in the exit of III grades of final filter cores, the exit linkage of miniature oil pump has the butt joint of a producing oil tube head, wherein oil feed butt joint tube head and advance oil pipe and link to each other enters the bottom that oil pipe placed the oil tank in, produce oil a butt joint tube head and an oil pipe link to each other, go out the upper portion that oil pipe placed the oil tank in. The utility model discloses have small, light in weight, convenient to carry, independent assortment, stable performance, convenient operation, reuse, realize the on-the-spot emergent transformer oil of filtration fast. There are extensive popularization prospect and in-service use meaning at electric power system.