The invention provides a Pt-loaded TiO2/hydroxyapatite core-shell composite photocatalyst, a preparation method and application thereof, wherein the core of the composite photocatalyst is TiO2 nanorods, the shell of the composite photocatalyst is hydroxyapatite, and the hydroxyapatite T shell is loaded with Pt, The length of the TiO2 nanorods is 150-500 nm, the diameter of the TiO2 nanorods is 50-80 nm, and the thickness of the hydroxyapatite shell is 2-10 nm. In the composite photocatalyst, a TiO2 phase and hydroxyapatite phase two-phase interface is in good and firm contact, and the hydroxyapatite layer covering layer is uniform and has strong thickness controllability.