The invention discloses a preparation method of TiO2 nanotubes with a controllable tube wall thickness, the preparation method is characterized by comprising the following steps of: (1) sequentially adding acetylacetone and tetrabutyl titanate into absolute ethyl alcohol to obtain a solution A; (2) adding polyvinyl pyrrolidone to the solution A to be completely dissolved to obtain a solution B; (3) dripping liquid paraffin into the solution B, and stirring for 48h to obtain a solution C; (4) filling the solution C into a syringe, performing electrostatic spinning under certain conditions, andcollecting a spinning product by using a stainless steel disc; and (5) after the spinning product is dried, calcining the spinning product at 500 DEG C in air atmosphere to obtain the TiO 2 nanotubes.According to the invention, the TiO2 nanotubes with different tube wall thicknesses are prepared by changing the ratio of the tetrabutyl titanate, the polyvinyl pyrrolidone and the liquid paraffin, and the light absorption capacity of the TiO2 nanotubes is further regulated and controlled.