Ferroelectric SrBi2Ta2O9 (SBT) thin films were prepared on Pt/TiO2/SiO2/Si(100) substrates by pulsed laser ablation of SrBi2.2Ta2O9 ceramic target. The ferroelectric properties and microstructure of SET films were investigated in this work. The SBT films deposited at 650 degreesC exhibited a remnant polarization of 6.6 muC/cm(2) and a coercive field of 23 kV/cm at 5 V. Higher leakage current was observed in films deposited at 550 degreesC. Crystallinity of the films was examined by X-ray diffraction patterns and no secondary phases were observed. Furthermore, XRD patterns also indicated a change in orientation from c-axis dominated to randomly polycrystalline, when the deposition temperature was changed from 550 to 650 degreesC. Grains in SET film show polyhedral morphologies based on planar TEM analysis. The microstructures of grain boundaries in SET him with c-axis dominated orientation were investigated by high-resolution transmission electron microscopy (HRTEM). The relationship between the leakage current of film and microstructures of grain boundaries is briefly discussed.