Abstract:The electronic structures, absorption spectra and colors of Cu are calculated. Calculations are performed in the GW approximation (GWA) approximation, where G refers to Green's function and W is the dynamically screened Coulomb interaction. The calculated absorption spectra and color of Cu based on the density functional theory and the GWA are presented, and the calculated results within the GWA agree well with measurements. The calculated results indicate that many-body effects play an important role for the quasi-particle property calculations of Cu.