Blue algae scavenger using expanded perlite as carrier and capable of floating on water

The invention relates to a blue algae scavenger using expanded perlite as a carrier and capable of floating on water and a preparation method thereof. The blue algae scavenger is prepared by wrapping a TiO2 pillared montmorillonite photocatalyst on the outer surface of the expanded perlite carrier and then drying, wherein the TiO2 pillared montmorillonite photocatalyst is prepared by adding a titanium pillared agent to a 2-3wt% sodium-based montmorillonite suspension, standing still and aging, centrifugally washing and drying, wherein the titanium pillared agent is prepared by hydrolyzing TiCl4 under a strongly acidic condition until the solution becomes colorless changed from yellow green and the ratio of the volume of TiCl4 to the weight of sodium-based montmorillonite is 0.8-1.2 mL/g. The blue algae scavenger using expanded perlite as a carrier and capable of floating on water provided by the invention has the advantages of convenience in use, quick acting, low cost, no secondary pollution and high adaptability, can be recycled easily and can be widely applied to various water areas polluted by blue algae.