The invention discloses a method for preparing a hierarchical porous TiO2/quantum dot composite material. The diameter of a hierarchical porous TiO2 particle is 5-500 nm, the material is a hierarchical porous material, the diameter of a quantum dot is 1-20 nm, and quantum dots are uniformly distributed on the surfaces of hierarchical porous TiO2 particles. According to the invention, the hierarchical porous TiO2/quantum dot composite material is prepared from a vacuum nanometer pouring method step by step, and the method includes the following steps: firstly preparing different quantum dot precursor solutions, weighing a certain amount of hierarchical porous TiO2 powder, adding the hierarchical porous TiO2 powder in the quantum dot precursor solutions in steps, pouring and adsorbing under a vacuum state, then drying and roasting to obtain the hierarchical porous TiO2/quantum dot composite material. The method reduces the synthesis cost of the material and has a simple process, in the prepared material, the quantum dots are uniformly distributed on the surfaces of TiO2 particles, and the material has a hierarchical porous structure and has great significance in the field of optoelectronic materials and photocatalytic materials etc.