PbZr 0.52Ti 0.48O 3(PZT) thin films were grown on Pt/Ti/SiO 2/Si substrates by RF-magnetron sputtering method. X-ray diffraction analysis shows that the PZT thin films annealed are polycrystalline. Ellipsometric spectra of PZT thin films were measured by using infrared spectrometric ellipsometry in the wavelength range of 2.5～12.6μm. The classical dispersion relation is used in the fitting for the PZT thin films, and the optical constants and thickness of the thin films were obtained. The thicknesses for the as-deposited PZT and annealed PZT thin films are 454.2nm and 450.3nm, respectively. The effective static charge obtained is |q|=1.769±0.024, which reveals that the charge transfer is not complete in the PZT thin films.