Uniform and transparent PbTiO 3 amorphous thin films were deposited on the quart glass substrate using a modified sol gel processing. The optical properties of PbTiO 3 amorphous thin films were investigated in detail. The refractive index was calculated and in good agreement with Cauchy function. The optical band gap of the PbTiO 3 amorphous thin films was obtained about 3.84 eV using semiconductor theoretical calculation. The FTIR spectrum investigation of the PbTiO 3 amorphous thin films shows that no absorption appears in the mid infrared region. Six IR active phonon modes were observed in the PbTiO 3 thin films annealed at 550℃ by far infrared reflectance spectra.