Since the growing interest in the manufacture and environmental applications of composites consisting of CuO and CeO2 nanoparticles. This work describes the CuO/CeO2 nanoparticle materials were synthesized by coprecipitation approach with aqueous solutions of copper nitrate and cerium nitrate. The nanocomposite particles were characterized by HRTEM, with a particle size around nanoscale particle sizes (~10 nm) with high dispersion phenomena. Further, cell cytotoxicity and the percentage cell survival was determined by using 3-(4,5-dimethylthiazol-2-yl)-5(3-carboxymethoxyphenol)-2-(4-sulfophenyl)-2H-tetrazoli um (MTS) assay on human fetal lung tissue cell (MRC-5). The experimental results show that the CuO/CeO2 nanoparticle materials only minor cause cytotoxicity effect in cultured human cells.