Rosiglitazone (RSG), C₁8H₁9N₃O₃S, is a thiazolidinedione insulin sensitizer. In this paper, the structure optimization of RSG and its Ag complexes was carried out at the level of LanL2d pseudopotential group of B3LYP/6-31+G(d, p)(C, H, N, O, S) and Ag atoms based on density functional theory (DFT). The Raman spectrum of RSG molecule and their silver complexes were obtained by frequency calculation, and the characteristic peaks of Raman spectra in the band 400-1800cm^-1 were identified. The surface electrostatic potential and frontier orbit of RSG molecule was calculated, and the possible sites of chemical reaction were analyzed. Using time-dependent density functional theory (TDDFT), the molecular internal excited state of RSG was calculated and analyzed, using the charge transfer spectra of RSG molecular internal relationship between the charge transfer was studied, The corresponding analysis was made with the ultraviolet spectrum measured by experiment. This provides important information for understanding the mechanism of RSG molecules.