This study was aimed to assess the antimicrobial  activity of  copper oxide nanoparticles (CuO NPs) created by  method of thermal green way using basically a maize starch. Mucoid were appeared of Klebsiella pneumoniae bacterial colonies and the positive results with some biochemical tests. On the other hand, Staphylococcus aureus  appeared pigmented colonies surrounded by a yellow halo because of mannitol fermentation.  According to the 24 time incubation period, the CuO NPs antimicrobial activity showed of bacterial growth pathogenic K. pneumonia was 0.52 ± 0.04 cell/ml than control 1.60 ± 0.01 cell/ml .Aven as S. aureus appeared the number of bacterial growth as follow 0.79 ± 0.07 cell/ml compared with control 1.90 ± 0.01 cell/ml. The biologically effect for enhancing antimicrobial activity the percentage of resistant was decreasing from 66.6% to 22.2% when used copper oxide nanoparticles. Also, S. aureus sensitivity test showed resistant percentage was decreased from 55.5% to 33.3% at 24 hours.