Abstract: The present invention relates to a method of preparing nucleic acid-inorganic hybrid nanoflowers, which comprises allowing a nucleic acid to react with a solution of a metal ion-containing compound at room temperature, thereby forming a complex between the metal ion and the nitrogen atom of an amide bond or amine group present in the nucleic acid. According to the present invention, organic-inorganic hybrid nanoflower structures may be synthesized using nucleic acid in a simple manner under an environmentally friendly condition without any toxic chemical substance. The produced organic-inorganic hybrid nanoflower structures show a high DNA encapsulation yield, have resistance against nuclease, and show significantly increased peroxidase activity. Thus, these nanoflower structures may be widely used as a gene therapy carrier and in biosensing technology.