The invention belongs to the technical field of nanomaterials. The invention provides a preparation method for a TiO2 nanomaterial with a hollow structure and application thereof in the field of photocatalysis. With alcoholic solvent as reaction medium and structure-directing agent, the preparation method first utilizes the polymerization reaction between phenol and aldehyde and ammonia initiation to synthesize phenolic resin polymer spheres (RF), titanium precursor is then hydrolyzed on the surfaces of the polymer spheres, and thereby an RF@TiO2 core-shell structure is formed. The organic matter core is then removed by roasting, and thereby the TiO2 nanomaterial with the hollow structure is obtained. The nano TiO2 which is obtained by adopting the method disclosed by the invention has the hollow structure, the diameter of the particle is as small as 20nm to 70nm, the degree of crystallinity is high, product purity is high, the pore volume is up to 0.1cm<3>/g to 0.4cm<3>/g, the specific surface area is 50m<2>/g to 200m<2>/g, and therefore the TiO2 nanomaterial has high photocatalytic activity; moreover, the preparation method is simple to operate, the reaction conditions are mild, templates can be easily removed without using strong acid and strong alkali, the TiO2 nanomaterial is environment-friendly, energy consumption is little, and the TiO2 nanomaterial is easy to popularize and use.