Sodium carboxymethyl cellulose/polyethyleneimine/graphene oxide (CMC/PEI/GO) nanocomposite films were prepared by a simple solution mixing-evaporation method. The anionic CMC and cationic PEI will be combined by ionic interaction. GO will also be a hydrogen bond with the CMC. The characterization and properties of CMC/PEI/GO nanocomposite films were analyzed using X-ray diffraction (XRD), scanning electron microscope (SEM) and universal testing machine (UTM). XRD and SEM were used to observe the structural properties and morphologies, respectively. UTM was used to analyze the mechanical properties such as tensile strength and Young’s modulus. It was found that the tensile strength and Young’s modulus of CMC/PEI/GO nanocomposite films were improved with a very small amount of GO. Keywords: CMC/PEI/GO films, tensile strength