Sb doped reactive sputtering-derived Pb(Zr,Ti)O-3 (Zr/Ti=48/52) thin films were investigated with the intention of improving ferroelectric properties. Also, the atomic valence of Sb in PZT thin film was confirmed as trivalent cation (Sb3+) by x-ray photoelectron spectroscopy (XPS). According to the tolerance factor t, Sb3+ tends to occupy the B-site of ABO(3) perovskite structure and acts as an acceptor that generates oxygen vacancies and holes. Transmission Electron Microscope(TEM) was used to observe the structural changes of PZT thin films by Sb addition. The leakage current densities and P-r of PZT thin films increased as the Sb contents increased. 0.7at% Sb doped PZT(PZST07) thin films exhibited improved fatigue properties (about 10% degradation of the remanent polarization after 10(10) switching cycles).