The invention discloses a delayed-lasing luminescent nano probe which is prepared from Au nanoparticles, a compact silicon dioxide isolating layer and a dye molecule doped silicon dioxide layer, wherein the surfaces of the Au nanoparticles are coated by the compact silicon dioxide isolating layer, the surface of the dye molecule doped silicon dioxide layer is covered by the compact silicon dioxideisolating layer, the dye molecules have triple excited states to form a three-energy-level structure, and resonant frequencies of the Au nanoparticles are matched with the triple-state energy levelsof the dye molecules. The invention further discloses a preparation method of the luminescent nano probe. A plasma lasing spectral line width of the luminescent nano probe disclosed by the invention is only about 3 nm, a lasing threshold value is as low as 1.0 mJ/cm<2>, and the luminescence lifetime is about 102 mu s; the luminescent nano probe can be applied to simultaneously detecting a great many channels, the detection accuracy is improved, and the luminescent nano probe is sutiable for biological detection; furthermore, the preparation method of the luminescent nano probe has the advantages of safety, high efficiency and suitability for large-scale popularization and application.