We have fabricated PMMA/SiO2 nanocomposite flexible thin films of 60 mim thicknesses by using solution casting method in the presence of transverse electric field. In this book, we have investigated the effect of SiO2 nanoparticle (NP)loading on optical and mechanical properties of the composite thin film. The SEM images show that nanocomposite thin films have a smoother and uniform morphology. The transmittance peak near 1103 cm-1 in FT-IR spectrum confirms the presence of SiO2 NPs in the composite thin film. It is observed that optical bandgap decreases with an increase in the SiO2 NP concentration. Dynamic mechanical analysis shows that presence of SiO2 NP enhances the mechanical strength of the composite thin film.