The invention provides a heat-dissipating powder coating modifying aid. The heat-dissipating powder coating modifying aid is prepared from such components in parts by weigh as 20-30 parts of nano kaolinite, 3-5 parts of corundum, 8-10 parts of phosphate ore, 3-10 parts of polyacrylate, 5-8 parts of aluminum dihydrogen phosphate, 5-8 parts of limestone, 1-1.5 parts of silane coupling agent and 0-0.7 part of bactericide. The preparation method of the heat-dissipating powder coating modifying aid comprises the steps of A, calcining the nano kaolinite and the phosphate ore at a temperature within the range of 650-750 DEG C, discharging and cooling, and then mixing the discharged material with the limestone, and grinding into powder, thereby obtaining a premix a, B, mixing the phosphate ore and the aluminum dihydrogen phosphate for ball milling, adding the polyacrylate in the ball milling process, stirring while preserving the heat within the range of 85-90 DEG C, thereby obtaining a premix b, C, mixing the premixes, adding the left raw materials and stirring for dispersing, and D, drying to obtain the coating modifying aid. The invention provides the heat-dissipating powder coating modifying aid capable of improving the adhesion of the heat-dissipating powder coating to the surface of an object, and the preparation method of the modifying aid; the aid is added to enhance the heat-conducting effect of the coating layer and improve the wear resistance of the coating.