The invention discloses an improved preparation method of ethylene glycol modified melamine formaldehyde resin. The method comprises the following specific steps: adding paraformaldehyde, melamine anddeionized water into a kneading machine provided with a heating and distilling device; adjusting a pH value of the materials to 9.5 +/- 0.5 by using a sodium hydroxide solution; raising a temperatureto 75 +/- 5 DEG C and carrying out a reaction for 1-2 hours; adding ethylene glycol, adjusting the pH value of the materials to 2.0 +/- 0.5 with an acid, carrying out a reaction for 0.5-1.0 h at a temperature of 75 +/- 5 DEG C, and evaporating water and remaining formaldehyde; heating the solid materials to a temperature of 150-200 DEG C, carrying out a reaction for 1-6 h, and cooling the materials to room temperature after the reaction is finished; and crushing the cooled materials into a powder product with a crusher. The preparation method disclosed by the invention has the advantages thatpreparation process and equipment are simple; basically no three wastes are discharged in the preparation process; ethylene glycol recovery and devices thereof are not needed; and the product basically does not contain chlorine, is low in water solubility and good in thermal stability and charring property, and can be used as a charring agent of an intumescent flame retardant.