The invention discloses a preparation method of porous titanium dioxide photocatalytic material. The preparation method comprises the following steps: (1) adding 3 to 7 parts by weight of lauryl amineinto an absolute ethanol solution, preparing into a 3.5 to 6 mmol/L solution, then adding 1.2 to 2 parts by weight of butyl carbonate, stirring and mixing for 10 to 60 min, heating for 10 to 36 hoursunder the temperature of 100 to 12 DEG C, centrifuging the reaction production to obtain solid product, cleaning the solid product for many times by using the mixed solution of ethanol and nitric acid, drying to obtain the porous titanium dioxide; (2) preparing a 5 to 7% titanium dioxide catalyst suspension; (3) preparing a hollow carbon fiber carrier; (4) immersing the hollow carbon fiber carrier into a titanium dioxide composite photocatalyst suspension for 20 to 60 min, taking out and drying; immersing the hollow carbon fiber carrier into the titanium dioxide photocatalyst suspension for 10 to 60 min, taking out and drying. According to the titanium dioxide photocatalytic material, the formaldehyde decomposition rate is rapid, the degradation rate is high and can reach up to 93%, and the degradation rate of methylbenzene reaches up to 69.7%.