Surface of gear that works continuously tends to be wore. Hardfacing on worn gear can repair its worn surface, restore its precision, consolidate its surface property, and save cost. Micro-Plasma Arc Welding (micro-PAW) has low heat input and narrow heat-affected zone, and it has good properties of energy concentration and high energy density. Therefore, hardfacing by micro-PAW is an effective method to repair worn gear surface. KF-Ni60A Ni-based alloy powder has good weldability property, and KF-Ni60A welding layer has low friction coefficient and good property of wear resistance between metallic hard surface, so it is a kind of good overlaying material that can be applied to the welding process to repair the worn gear surface. In this research, the method of overlaying on worn gear using KF-Ni60A Ni-based alloy powder by micro-PAW is studied. The microstructure of deposition layer and the elementary distribution of cross-section are analyzed, the surface hardness and wear resistant property of the layer are measured. The result indicates that the deposition layer and the base metal bond well, the layer has high adhesive strength and hardness, low porosity, and good property of wear resistance.