The invention relates to a method for improving the thermal property of a cooling tower packing, which comprises the following steps: uniformly adding powder salt on the surface of a packing flat sheet which is ready to be formed before the last pair of rollers in the process of injection molding polyvinyl chloride into the packing flat sheet, pressing the powder slat into the surface of the sheet during the process of pressing the next pair of the rollers, and leading the powder salt to be uniformly distributed on the upper surface and the lower surface of the packing sheet after molding; and then placing the packing sheet in a clean water tank for standing, dissolving the salt into water and taking out the packing sheet which is a finished product. The method can increase the surface roughness of the packing sheet, change the hydrophilicity of a material, increase the air-water contact specific surface area, lead circulating hot water to be easier to form a water film on the surface of the packing sheet, prolong the downward flowing time of the water film due to the surface roughness, increase the heat exchange time and improve the cooling effect of a cooling tower by changing the surface microstructure of the packing sheet.