In order to fabricate effective bifunctional oxygen catalyst, IrO2 nanoparticles have been synthesized by hydrothermal method, and Pt/IrO2 bifunctional catalyst is then prepared by a microwave-assisted polyol process. X-ray diffraction and transmission electron microscopy are employed to characterize the catalysts, which reveal that Pt with a particle size of 2-3 nm is deposited on IrO2 surface. Electrochemical tests indicate that Pt/IrO2 bifunctional catalyst possesses much higher catalytic activity and durability towards both oxygen reduction reaction and oxygen evolution reaction than pure Pt or pure IrO2. Kinetic analysis shows that the oxygen reduction reaction on Pt/IrO2 catalyst mainly follows four-electron pathway.