3The Research & Test Center of Materials, Wuhan University of Technology, Wuhan 430070, ChinaThe highly oriented perovskite-phase PT/PZT/PT ferroelectric thin film was prepared by sol-gel method. The domain structures and polarization retention properties were investigated by scanning force microscopy. The amplitude and phase images of piezoresponse show complex various contrasts of dark, bright and gray.The complex variation of contrast in piezoresponse images results from the perplexing orientation of grains and arrangement of domains in the ferroelectric films.The bright and dark areas in phase images correspond to top-to-bottom and bottom-to-top polarization oriented c-domain, respectively. The gray areas are c-domains with the polarization vector deviating from the direction normal to the film plane. The surface potential images of EFM are bright contrast, which is due to positive charges trapped on the film surface after being polarized by positive voltage. And the brighter contrast is obtained from the higher electric field. The time-dependent surface potential images and line potential profiles show that the potential decays with time. And the decay in the region polarized by higher electric field is faster, especially at 15 min. This indicates that the polarization retention is related to the polarized electric field. Better retention properties may be obtained from a proper polarized electric field.