In order to explore the loading mode of modified TiO₂ photocatalyst and melamine sponge，self-floating photocatalyst with excellent performance was prepared and applied to the inactivation of red tide microalgae. The results showed that the loading capacity and loading strength of photocatalyst by gel method were higher than those by coating method，respectively 0.165 g and 96.72%，which was a more stable loading mode of modified photocatalyst and melamine sponge. The 4 h inactivation rate of the prepared floating photocatalyst for Karenia mikimotoi was as high as 86.25%，and the 96 h growth inhibition rate was as high as 81 .25%. The experiment also showed that photocatalysts disrupt cellular metabolic activity by degrading chlorophyll and proteins within microalgae cells，ultimately leading to their inactivation. The self-floating photocatalyst prepared by our research institute not only exhibits excellent algal removal effect，but also has stable recovery performance，which is expected to provide new ideas for the harmless treatment of harmful red tide outbreaks.