The invention discloses a preparation method and application of a Pt@MOFs/TiO2 optical catalyst. The preparation method comprises the steps that a double solvent method is adopted, firstly noble metal nanoparticles and a prepared MOF organic solvent are subjected to self-assembly, then Pt@MOFs is obtained under the condition that a reducing agent exists, finally TiO2 is evenly dispersed in an aqueous solution of Pt@MOFs, and the MOFs optical catalyst of a three-layer structure is obtained. The prepared optical catalyst can be widely applied to fields of waste water treatment, atmospheric purification and the like. The prepared optical catalyst improves the separation rate of photo induced electron-electron hole, can not only make compounded pollutants separated from each other, but also process the pollutants synchronously and finally improves the photocatalytic efficiency; due to the improvement of the separation rate of photo induced electron-electron hole, the photocatalytic efficiency of the optical catalyst for a single pollutant is also improved.