The invention relates to a process for preparing diatom earth loading nanometer Ti2O material for purifying water and air, which belongs to the field of material process and environmental treatment. Diatom earth raw ore is filled with water and is churned and scattered, is screened, is sunken by gravity, and is eccentrically sunken, sulfuric acid is adopted to dissolve clay-type foreign matters which are left in pore passages after ores which mutually grow with diatom earth like quartz, feldspar, mica, and clay and the like and organic matters which are mixed such as grass roots and barks and the like are removed, and diatom fine soil is attained. Further, diatom fine soil is filtered, dried, and baked, and diatom fine soil after baked is filled with water, and is churned, and is filled with acid to regulate the PH value, and is filled TiCl4 solution, and is filled with ammonia sulfate solution to proceed hydrolytic decomposition deposition reaction, and product yield after the reaction is filtered, washed, dried, and baked to attain the nanometer Ti2O material.