Plumbagin (PLB), a naphthoquinone compound exhibiting significant antitumor activity, has its clinical application limited due to cellular toxicity. This study investigated the adsorption mechanism and Raman spectroscopic properties of PLB interacting with gold clusters of varying sizes (Au 2, Au 4, Au 6, Au 8) using density functional theory (DFT). Based on the surface enhancement of Raman scattering (SERS), the orientation of the PLB molecule on the gold substrate surface was inferred, and their interactions were investigated. The results indicate that PLB adsorbs vertically onto the surface of Au n cluster via the O13 atom, forming stable complexes. Among these, the PLB-Au 4 complex exhibits the strongest binding energy (-64.80 kJ·mol -1) and the shortest bond length (2.2403 Å). Raman spectrum analysis revealed that the characteristic peaks of the complexes are ”selectively” enhanced due to changes in the local environment of the atoms closer to the Au n cluster in the molecule of PLB, induced by charge transfer effects. Furthermore, frontier molecular orbital analysis demonstrated that the introduction of Au n clusters significantly reduces the energy gap of the system (maximum reduction of 47.45%), thereby enhancing the chemical reactivity of PLB. This work provides experimental evidence and theoretical support for improving the bioavailability of PLB and developing a new drug delivery platform based on PLB combined with Au nanoparticles complex