A nano phosphating solution comprises, by weight, 400-500 parts of phosphoric acid, 60-90 parts of zirconium oxide, 140-180 parts of zirconium nitrate, 15-30 parts of ethylene diamine tetraacetic acid and 400-460 parts of water. A preparation method of the nano phosphating solution comprises the following steps that 40%-60% of water of the whole needed water amount is added in a glass container; the phosphoric acid is added and stirred evenly; the zirconium oxide is added and stirred for two to three hours; after the zirconium oxide is completely dissolved, the zirconium nitrate is added; then the ethylene diamine tetraacetic acid is added and stirred for one to two hours; after the ethylene diamine tetraacetic acid is stirred to be dissolved completely, the rest water is finally added; and then the nano phosphating solution is obtained. The thickness of a phosphating film formed by the nano phosphating solution is no more than 200 nanometers, the size of a phosphating crystalline particle is no more than 200 nanometers, corrosion resistant performance is good, binding force with a base body is high, and adhesive force of paint is also increased.