The invention discloses a preparation method of TiO2 nanoparticles with photonic crystal characteristics. The preparation method comprises the following steps: preparing a precursor solution by mixing TiCl4 solution, absolute ethyl alcohol and deionized water; and with butterfly wings as a bio-template, treating the template by a solution impregnation method and removing the template at a high temperature to obtain the TiO2 nanoparticles. The preparation method disclosed by the invention has the advantages of simple technology, easily available raw materials, good product structure and performance and the like; and the prepared TiO2 nanoparticles with photonic crystal characteristics have a good application prospect in the field of thin-film solar cell study.