The polyimide-silica nonlinear optical (NLO) hybrid materials with covalent links between the inorganic and the organic networks were synthesized by the sol-gel method. The prepared hybrids were characterized by IR, TGA, XRD, SEM, TEM and can be easily spin-coated, ensuring long-term alignment stability at elevated temperatures. These devices exhibit large electro-optic coefficients at 832 nm. The experimental results suggest that the hybrid thin films have potential applications as passive films for optical devices.