The Au@TiO2: Yb, Er core-shell nanostructures were firstly synthesized by a modified hydrothermal method and ion diffusion process. The broadband upconversion emission of the as-prepared core-shell nanostructure could be attributed to thermal radiation generated by high temperature because of the photothermal effect of gold nanomaterials. The products have potential applications in solar cells, light-emitting diodes, biosensors and photocatalysis.