The invention provides a TiO2 material with a three-dimensional structure and a preparation method and application thereof. The TiO2 material comprises a three-dimensional flower-like microsphere structure composed of multiple TiO2 nanowires emitted from the center in a radial manner, wherein the particle sizes of the three-dimensional flower-like microspheres are 3-6 microns, the diameters of the nanowires are 20-50nm, and the length of the nanowires is 1.5-3 microns. The preparation method of the three-dimensional flower-like TiO2 material comprises the following steps of dissolving metal Ti powder in a mixed solution of H2O2/HNO3, and performing a hydrothermal reaction with sodium hydroxide at certain temperature; after the reaction, performing centrifugal separation and washing until the pH value of the solution is 7; drying in an oven. The three-dimensional flower-like TiO2 material provided by the invention has higher adsorption property and photocatalysis property than Degussa P25 nano TiO2 in degrading methylene blue dyes.