Metallic nanoparticles complex thin film is a new kind of promising photoemissive thin film because of its perfect photoemissive properties and extremely fast optical response- We obtained a light-emitting Ag-BaO nanometer thin film using vacuum deposition method- Red-blue-violet range light emission was observed from its photolumine-scence(PL)- We believe that the origin of PL of Ag-BaO thin film is the contribution of the Ag nanoparticles- Compared with its ultraviolet-visible absorption spectra, the mechanism of its PL covering different visible light ranges was analyzed-