Due to the scientific, industrial, electrical and medical importance, it was necessary to study the properties of overlapping nanocomposites. So it gained the attention and directed scientists and researchers in the study of its structure and electrical characteristics and other characteristics. So, In the present work, (polyvinyl alcohol- polyethylene oxide- manganese oxide nanoparticles) nanocomposites have been prepared with different concentration of blend and MnO2 nanoparticles. The manganese oxide nanoparticles were added to (PVA-PEO) blend by weight percentages are (2, 4 and 6) wt.%. .The optical microscope images indicate that the manganese oxide nanoparticles additive distribution was homogeneous in the (PVA-PEO) blend. FT-IR indicate that no change on chemical structures between the (PVA-PEO) blend and manganese oxide nanoparticles additives. The dielectric properties of nanocomposites were studied.The results showed that the dielectric constant, dielectric loss and electrical conductivity of (PVA-PEO) blend are increased with the increase in concentrations of manganese oxide nanoparticles. The dielectric constant and dielectric loss decrease while the AC electrical conductivity increases with the increase in frequency of applied electric field. Optical measurements are showed the absorbance of(PVA-PEO-MnO2) nanocomposites is increased with increase of the concentrations of MnO2NPs.With increasing of the concentrations of manganese oxide nanoparticles, the indirect energy gap (Eg) of (PVA-PEO) blend will be decreased. And by increasing of the weight percentages of manganese oxide nanoparticles,the optical constants as absorption coefficient, extinction coefficient, refractive index, real and imaginary dielectric constants of nanocomposites are varied.