We studied the effect of the surface functionalization and crystalline phase change of poly(vinylidene fluoride) (PVDF) films on their adhesion and piezoelectric properties. The surface modification of PVDF was carried out with ion beam and/or plasma treatment. These surface modifications were found to alter the interfacial strength between PVDF and metal electrodes and the crystal structure of the piezoelectric PVDF film. A remarkable improvement was found in the interfacial adhesion of the films with thermally deposited metal electrodes, but some piezoelectricity of PVDF film was lost due to the changes in the crystal phase. The proper treatment condition for enhancing the adhesion and retaining piezoelectric structure was suggested.