Plasmonic nanostructures, particularly those composed of noble metals such as gold and silver, have garnered extensive attention due to their exceptional physical and chemical properties, which are highly advantageous for optical sensing applications. The unique characteristics of DNA enable the precise spatial arrangement and functionalization of nanoparticles, allowing for the tailoring of optical characteristics within plasmonic systems. This review encompasses the development of DNA nanotechnology and its application in constructing plasmonic nanostructures featuring diverse geometric configurations. It emphasizes the tailored optical responses of these structures, including surface-enhanced Raman scattering (SERS), fluorescence enhancement, and chirality. The review concludes with a discussion of the opportunities and challenges facing DNA-based plasmonic nanostructures.