A sandwich structure for enhancement of photoluminescence (PL) from luminescent films and the corresponding preparation method are disclosed. The sandwich structure comprises a support, a luminescent film grown on the support, and a single-layer close-packed microsphere array deposited onto the luminescent film. The microspheres have high transmittance excitation light and emitted light, respectively. The low price of dielectric microspheres is beneficial to industrial applications. The stable chemical properties of dielectric microspheres make PL enhanced in a long term. Both metal and non-metal materials can be used as the support in the sandwich structure. These features significantly improve the technique of PL enhancement for luminescent films.