In this work, the (PEO-PVA-Sb 2 O 3 ) nanocomposites were prepared from (PEO-PVA) blend with different concentrations of the Sb 2 O 3 nanoparticles by using the casting method to used it for different modern applications such as: antibacterial, humidity sensors, solar cells, diodes, thermal energy storage and release …etc. The structural, optical and dielectric properties of (PEO-PVA-Sb 2 O 3 ) nanocomposites have been studied. The results of optical properties for nanocomposites showed that the absorbance has high values at UV region. Also, its increase while the transmittance and energy band gap reduce of (PEO-PVA) blend with the increase in Sb 2 O 3 nanoparticles concentrations. The absorption coefficient, extinction coefficient, refraction index, dielectric constant and optical conductivity are increased with the increase in Sb 2 O 3 nanoparticles concentrations. The dielectric properties of nanocomposites showed that the dielectric constant, dielectric loss and A.C electrical conductivity of (PEO-PVA) blend increase with the increase in Sb 2 O 3 nanoparticles concentrations. Also, the dielectric constant and dielectric loss of (PEO-PVA-Sb 2 O 3 ) nanocomposites decrease while the A.C electrical conductivity increases with the increase in frequency. finally, the (PEO-PVA-Sb 2 O 3 ) nanocomposites tested for antibacterial applications. The results showed that the the (PEO-PVA-Sb 2 O 3 ) nanocomposites have good activity for antibacterial.