We have studied grain-shape dependence of Kelvin probe force microscopy of SrBi2Ta2O9 thin films on epitaxial La0.5Sr0.5CoO3/LaAlO3 substrates. By changing the growth condition in pulsed laser deposition, we have grown the SrBi2Ta2O9 thin films with various grain shapes. The shape and the orientation of SrBi2Ta2O9 the thin films with various growth conditions have been analyzed by X-ray diffraction and scanning electron microscope. The large number of the long rectangular grains was observed accompanied with relatively larger (220) peaks than other peaks. From the Kelvin probe force microscope study, it has been observed that the long rectangular grains showed characteristics of easy ferroelectric domain switching at a low writing bias and weaker influence of surface charges. (c) 2005 Elsevier B.V. All rights reserved.