In this paper, Ni-plated ZrO2 reinforced alloy was prepared by thermal decomposition and reduction method, and Ni-plated ZrO2 reinforced Sn1.0Ag0.5Cu composite filler metal was prepared by powder metallurgy method. The surface metallization of ZrO2 nanoparticles and its effect on the microstructure, material properties and brazing joints of Sn1.0Ag0.5Cu composite filler metal were studied. The results showed that the particle size and agglomeration of ZrO2 decreased after mechanical pretreatment. The Ni-plated ZrO2 enhanced phase was successfully prepared by thermal decomposition and reduction method. The Ni particles were uniformly attached to the surface of ZrO2 with a spacing of 8-11 nm, and the interface between ZrO2(02) and Ni(11) showed a semi-coherent relationship. The melting point and resistivity of Ni/ZrO2-Sn1.0Ag0.5Cu composites were not significantly affected by adding a proper amount of nickel-plated ZrO2, but the wettability and tensile strength were improved. The tensile strength and shear strength of brazed joint of Ni/ZrO2-Sn1.0Ag0.5Cu composite filler metal reach the peak when the adding amount of ZrO2 reinforcing phase is 0.7 wt.%, which are increased by 43.3% and 40% compared with the matrix material. With the addition of Ni/ZrO2 reinforcing phase, the fracture position of the brazing joint of the composite filler metal moves from the interfacial IMC layer to the side near the brazing seam in the transition zone, and the fracture mechanism gradually changes from the mixed tough-brittle fracture to the ductile fracture dominated by dimple.