The invention discloses direct welding polyester imine enamel wire paint and a preparation method thereof. Firstly, polyester imine resin generates from monacid, aromatic dicarboxylic acid, 4-methacryoxypropyl, 4, 4'-diaminodiphenyl-methane, trihydric alcohol, triethanolamine, dihydric alcohol and monoethanolamine through the melt copolycondensation under the function of catalyst; secondly, modified etherifying amino resin is prepared from melamine, urea, benzoguanamine, 37 percent of formaldehyde, methanol, isopropanol and normal butyl alcohol through the hydroxymethylation and etherification; thirdly, modified etherified phenolic resin is prepared from technical xylenol, isopropylidene diphenol, boric acid, 37 percent of formaldehyde, methanol, isopropanol and normal butyl alcohol through the hydroxymethylation and etherification; finally, three products obtained through the three steps are mixed with mixed environmental solvent according to the quality ratio of 1-1.9 to 0.2-0.9 to 0.2-0.9 to 8 to obtain the direct welding polyester imine enamel wire paint. The enamel wire painted through the enamel wire paint of the invention can be welded directly under the condition of not higher than 400 DEG C and the stretch of the enamel wire paint or the fluting of zero pinhole can be realized.