The invention provides an oil dirt powerful cleaning agent and a preparation method thereof. The oil dirt cleaning agent comprises the following components in parts by weight: 35-50 parts of oil, 21.5-53.5 parts of water, 1-5 parts of cationic surfactant, 1-5 parts of anionic surfactant, 1-5 parts of nonionic surfactant, 8-12 parts of cosurfactant n-butyl alcohol, 0-0.5 part of sodium chloride and 0.5-1 part of builder sodium tripolyphosphate. The oil dirt cleaning agent has the beneficial effects that the oil dirt cleaning agent uses compound microemulsion of the anionic/cationic surfactant with stronger solubilizing capacity and the nonionic surfactant with degradability as mother liquor and adopts several property assistants, so that the oil dirt cleaning agent achieves the advantages of rust prevention and decontamination, multiple reutilization of the lotion and environment friendliness, does not have limits to the oil content and has great economic value; meanwhile, the oil dirt cleaning agent also achieves diversification of cleaning objects, can be used for the materials, such as metals, glass, plastics, cloths, leather, ceramics and rubber and has a better application prospect.