By using laser cladding technology, a nano-Y2O3/Co-based composite coating was prepared in the Ni-based alloys substrate with Nano-Y2O3 and cobalt based alloys powder. The microstructure, micro-hardness wear resistance of the composite coating were researched by scanning electron microscopy (SEM) and other testing methods. The results show that the micro-hardness of laser cladding is HV868, and the welded surfacing layer is only HV512. Wearing values are decreased by 25.6 mg of the surfacing layer to 0.5 mg of the laser cladding layer in the wear testing of 40 minutes. The wear resistance of laser cladding layer is 51 times of the the wear resistance of the surfacing layer using the Co-28Cr-4W-1C electrode. The microstructure of laser cladding layer consists of the fusion zone, the fine equiaxed dendrite zone and the coarse crystalline zone.