In this study, casting technique were used to fabricate of PEG/Fe2O3 nanostructures with variant content of Fe2O3 NPs to employ in different optical fields. The results showed that the absorbance of PEG increases as the concentrations of Fe2O3 nanoparticles increase while the transmittance and energy gap of PEG decrease with increase concentrations of Fe2O3 NPs. The optical factors of PEG/Fe2O3 nanocomposites are enhanced with adding of the Fe2O3 NPs content. The optical characteristics results of the PEG/Fe2O3 nanocomposites proved that may be employed in optoelectronic detector.