Abstract: The silicon-based composite films（SiO_xC_y and SiO_xN_y） are prepared by Dual Ion Beam Sputtering and annealed at different temperature respectively.Subsequently the films luminescence and structure properties are characterized by PL,FTIR and XPS.There are two luminescent peaks from films are observed by PL and their intensity will enhance with increasing annealing temperature.The same peak at 470nm for two films usually is ascribed to neutral oxygen vacancy（O₃≡Si-Si≡O₃） which is likely come into being the centre of luminescence.Moreover,combining with FTIR and XPS we draw the conclusion that another peak at 420nm（for SiO_xC_y） or 400nm（for SiO_xN_y） is related to doping with C or N which interacted with Si and O from silicon-based film and formed the structure of SiO_xC_y or SiO_xN_y.