Films of (polyvinyl alcohol- silicon dioxide) nanocomposites were prepared for UV- shielding with low cost, low weight and excellent anti-UV properties. Studying the structural and optical properties of PVA/SiO2 nanocomposites have been investigated. The experimental results showed that the absorbance (A), absorption coefficient (), extinction coefficient (K), refractive index (n), real (ε1) and imaginary (ε2) parts of dielectric constants and optical conductivity (σop) of PVA are increased with increasing of the SiO2 concentrations. The transmittance (T) and energy band gap (Eg) decrease as a SiO2 concentrations increase. Also, te results showed that (PVA-SiO2) nanocomposites can be used for flexible solar cells, diodes and transistors applications.