In this research copper oxide (CuO) nanoparticles were prepared by sol gel method. In this method CuCl 2 .2H 2 O was used as precursor, the obtained CuO nanoparticles were further supported by alumina to produce copper oxide support on alumina catalyst, the copper oxide nanoparticle and the catalyst were characterized using different analytical techniques such as titrimetric method, x-ray diffraction (XRD), Scanning Electron Microscope (SEM) and the catalyst was applied in the synthesis of tetraethyl orthosilicate (TEOS). The obtained results indicated the formation of copper oxide nanoparticles and copper oxide supported in alumina catalyst in high quality, also the catalyst increased the rate of formation of tetraethyl orthosilicate (TEOS).