The invention discloses titanium dioxide nano-particles with a multi-defect fluorine doped hollow burr cubic structure and a preparation method thereof. The titanium dioxide has a grain size of 200-300nm and a specific surface area of 190-200cm<3>, and has a large hollow cubic structure formed by self-assembly of small titanium dioxide nanosheets mainly exposing [001] crystal faces. The preparation method comprises the following steps: firstly, synthesizing NH4TiOF3 mesoscopic crystal by respectively using tetrabutyl titanate and ammonium fluoride as a titanium source and a fluorine source byusing a hydrothermal method; further treating the sample with boric acid; releasing a great quantity of fluorine ions while transforming NH4TiOF3 into titanium dioxide through a topological transforming process to obtain the titanium dioxide hollow nano-cube formed by self-assembly of a great quantity of small titanium dioxide nano-sheets exposing high-activity [001]crystal faces; and introducinga great quantity of vacancy to the surface of titanium dioxide by adopting a photo-reduction method, and doping fluorine at the same time. According to the preparation method, the energy gap of titanium dioxide can be remarkably reduced by introducing oxygen vacancy, multiple reflection of light can be realized by the hollow structure, and the light absorption efficiency can be improved.