In this stud PZT thin films were prepared on Pt substrate using crystallized PZT dots as a seed for formation of large grained PZT thin films through lateral growth. Effects of the grain boundaries on the electrical properties of thus obtained PZT thin films were investigated by locating the upper Pt electrode of about 8$mu extrm{m}$ in a diameter right on the grain boundaries in a controlled manner. t turned out that when there was no grain boundary the best ferroelectric and electrical performance could be obtained as expected. Pr(remanent polarization) JL(leakage current density) at 2V and EBD (breakdown field) were found to be 30${mu}$C/cm2 8.47${ imes}$10-8 A/cm2 and 1.24MV/cm respectively. When one-grain boun-dary was contained in the area measured Pr=21${mu}$C/cm2, JL==1.24${ imes}$10-5 A/cm2 at 2V and EBD=0.64MV/cm. More drastic change could be observed in fatigue test. No appreciable degradation in the ferroelectric peroformance could be observed in grain boundary free PZT films up to 2${ imes}$1011 cycles at 1 MHz. However serious degradation could be observed after 4.4${ imes}$106 cycles when one-grain boundary was contained and after 1.4${ imes}$104 cycle when four-grain bondaries were contained in the area measured,