Dopamine polymerization reaction and hydrothermal method was used to prepare nickel coated alumina reinforcement phase; Preparation of nickel coated alumina (Ni/Al2O3) reinforced Sn1.0Ag0.5Cu (SAC105) composite material alloy using traditional casting method; The result showed that the nickel coating layer was continuous but with uneven thickness.The strength, toughness, and wettability of the SAC105 solder with the substrate have been im-proved, while the conductivity has not decreased significantly. The optimal doping amount was determined by comprehensive analysis when the doping amount of the reinforcing phase was 0.3wt%. The fracture mode of composite material alloy has shifted from a mixed mode of toughness and brittleness to a pure toughness fracture mode composed only of a large number of dimples.The prepared composite brazing material was made into solder paste for copper plate lap joint experiments. The maximum shear strength was achieved when the doping amount was 0.3wt% The growth index of IMC at the brazing interface of Ni/Al2O3 reinforced Sn1.0Ag0.5Cu composite brazing material was linearly fitted to n=0.39, which can be used to determine the joint effect of grain boundary diffusion and bulk diffusion on the growth of IMC at the interface