The invention relates to a method for preparing porous microspheres, in particular to a method for preparing anatase-TiO2 porous microspheres. The method solves the problems that the existing TiO2 porous microsphere has complex manufacturing process, high temperature during the preparation process, high price of the precursor used in the manufacturing process, high toxicity, and manufactured TiO2porous microsphere is rutile type. The method comprises the following steps: firstly, preparing dihydrate titanous sulfate solution; secondly, performing natural cooling after drying to obtain white precipitate; and thirdly, performing alternate cleaning with distilled water and absolute ethyl alcohol, and then performing drying to obtain the anatase-TiO2 porous microspheres. The preparation method has the advantages that the process is simple, the temperature is low during the preparation process, of the precursor used in the manufacturing process is low in price and nontoxic, the obtained TiO2 porous microspheres are anatase type and the organic matter in the water body is easy to be removed.