The invention relates to a preparation method of sun-screening agent for decorative paper production, and belongs to the technical field of sun-screening agent. The sun-screening agent loaded with nanometer titania is prepared by taking kaolinite, polyethylene glycol and nanometer titania as raw materials, and mixing materials in a desalting water and forming slurry; delivering the slurry to a grinding machine to grind, wherein the grinding process includes preparation of nanometer kaolinite, , dispersion of nanometer titania, and loading of nanometer titania; realizing intercalation and modification of kaolinite by nanometer titania through a mechanical force chemical intercalation process of the kaolinite; then performing dispersing, aging, drying, breaking and other procedures to obtain the sun-screening agent. The preparation process is free from waste water, the technique device is simple and the operation is also simple; the nanometer titania is nanometer TiO2 aggregate for the SCR denitration catalyst carrier; the technical and environment protection problems of preparation of nanometer TiO2 are eliminated, the production process is simplified; the sun-screening agent for decorative paper production can improve the sun-screening and anti-aging performances of the decorative paper.