Using the pseudo-potential plane-wave based on the density functional theory (DFT), the band structure, electron density of states and optical properties of intrinsic ZnS, N-, Cu -N and Cu-2 N co-doped ZnS were calculated. The calculation results show that the co-doped systems can reduce the band gap and enhance its Photocatalytic properties. According to the Analysis of the density of states, the co-doped system of Cu-2N make the state density become more diffuse, more state density through the Fermi level, which obviously led to formation of p-type ZnS. At some time, Cu/N co-doping greatly increase the absorption of visible region owing to the lower transition energy of co-doped systems .
