A recombinant fluorescent protein nanoparticle having high fluorescence intensity and a method of detecting a target material using the same are provided. The protein nanoparticle has higher fluorescence intensity than a fluorescent protein, and is resistant to denaturation of the fluorescent protein at room temperature, thereby having higher structural stability than the fluorescent protein itself. In addition, since a self-assembled protein is used as a fusion partner of the fluorescent protein, the protein nanoparticle is biocompatible and safe. Moreover, when a linker peptide is additionally inserted into the protein nanoparticle, a suitable distance between the self-assembled protein and the fluorescent protein is maintained, thereby considerably increasing fluorescence intensity of the protein nanoparticle. The probe-binding protein nanoparticle can control distances between the fluorescent proteins on the surface thereof, thereby maximizing fluorescence intensity.
