This work considers the CuO/La2O3/CeO2 nano-rare earth composite materials were synthesized by coprecipitation method with aqueous solutions of copper nitrate, lanthanum nitrate and cerium nitrate. The performance of the selective catalytic oxidation of ammonia to N2 (NH3-SCO) over a CuO/La2O3/CeO2 nano-rare earth composite materials in a tubular fixed-bed reactor (TFBR) at temperatures from 423 to 673 K in the presence of oxygen was reported. The catalytic redox behaviors were determined by cyclic voltammetry (CV). Further, cell cytotoxicity and the percentage cell survival were determined by using MTS assay on human fetal lung tissue cell (MRC-5). The experimental results show that the CuO/La2O3/CeO2 nanocomposite particles only minor cause cytotoxicity effect in cultured human cells.