In this work, IrO 2 thin films as bottom electrode of ferroelectric capacitors were deposited and characterized. The IrO 2 films deposited in the conditions of 25, 40 and 50% oxygen ambient by sputtering method were annealed at 600, 700 and 800 ? C , respectively. It was found that the crystallinity and the surface morphology of IrO 2 films affected the surface properties and electrical properties of SBT thin films prepared by the MOD method. With increasing temperature, the crystallinity and the roughness of IrO 2 films were also increasing. This increasing of roughness degraded the surface properties and electrical properties of SBT films. We found an optimum condition of IrO 2 films as bottom electrode for ferroelectric capacitor at 50% oxygen ambient and 600 ? C annealing temperature. Electrical characterizations were performed by using IrO 2 bottom electrodes grown at an optimum conditions. The remanent polarization ( P r ) of the Pt/SBT/ IrO 2 / SiO 2 /Si structure was 2.75 μ C/ cm 2 at an applied voltage of 3 V. The leakage current density was 1.06 {\times}10 ?3 A/ cm 2 at an applied voltage of 3 V.