The silicon-containing polyimide/BaTiO3 nanocomposite films were prepared by mixing the silicon-containing poly(amic acid) based on bis(3,4-dicarboxyphenyl)dimethylsilane dianhydride and 4,4'-Oxydianiline with BaTiO3 nanoparticles, followed by thermal imidization. Structure and properties of the nanocomposite films were measured with FTIR, SEM, XPS and DMTA. The results indicated that the interfacial interaction between BaTiO3 nanoparticles and the silicon-containing polyimide was conspicuous, and that BaTiO3 nanoparticles appeared to be better dispersed in the polyimide matrix at a higher BaTiO3 concentration than at a lower one. The siliconcontaining polyimide/BaTiO3 nanocomposite films exhibited higher storage modulus and glass transition temperature than the original polyimide. It was also found that the infrared emissivity of the nanocomposite films varied with the content of BaTiO3 in the nanocomposites, and the nanocomposite films exhibited lower infrared emissivity value than the corresponding polyimide by measure of infrared emissivity.