Abstract: A luminescent element comprises: a luminescent substrate; and a metal layer with a metal microstructure formed on a surface of the luminescent substrate; the luminescent substrate comprises luminescent materials with a chemical composition of Y3AlxGa5-xO12:Tb, and 0?x?5. A preparation method of a luminescent element and a luminescence method are also provided. The luminescent element has good luminescence homogeneity, high luminescence efficiency, good luminescence stability and simple structure, and can be used in luminescent device with ultrahigh brightness.