The (PS-Cr2O3/ ZnCoFe2O4) nanocomposites have been fabricated by solution casting method with different weight percentages of Cr2O3 nanoparticles and ZnCoFe2O4 are (0,2,4,6 and 8) wt.% for UV and microwave shielding applications.. The structural and optical of (PS-Cr2O3/ ZnCoFe2O4) nanocomposites have been studied. The structural properties include Fourier transform infrared spectroscopy (FTIR). The results of structural properties for spectroscopy (FTIR) showed shift in peak position as well as the change in shape and intensity compared with pure polystyrene. The results of optical properties for (PS-Cr2O3/ZnCoFe2O4) nanocomposites showed that the absorbance, absorption coefficient, dielectric constants and optical conductivity of polystyrene were increased with the increase in Cr2O3 nanoparticles concentrations while the transmittance and energy band gap were decreased with the increase of the Cr2O3 nanoparticles concentrations. The (PS-Cr2O3/ZnCoFe2O4) nanocomposites have high absorbance in the UV-region. The results of structural and optical properties showed that the (PS-Cr2O3/ ZnCoFe2O4) nanocomposites may be used for UV and microwave shielding.