Alumina ceramics were joined with Ag-10CuO-10B2O3 filler via reactiver air brazing for the formation of whiskers (Cu2Al6B4O17) in the joints. The effects of brazing temperature and holding time on the microstructure, properties of the joints and the whisker structure were investigated. The results show that Al2O3 reacts with CuO and B2O3 to form Cu2Al6B4O17 whiskers in the brazing process, thus obtaining a reliable joint with the superior performance. At the holding time of 60 min and the brazing temperature of > 950 ℃, an effective connection of Al2O3 ceramic joint can be realized. The center area of the brazing joint is mainly Ag, while the interface at the both sides of the joint is composed of CuO、Cu3B2O6 phase and Cu2Al6B4O17 whiskers. The shear strength of the joint increases with the increase of the brazing temperature. The whiskers become thick and the adhesion occurs when the brazing temperature is > 1 050 ℃, thus reducing the strengthening effect on the joint and the shear strength of the joint. The whiskers decompose into some lamellar products, and the shear strength of the joint decreases when the brazing temperature is > 1 100 ℃. The shear strength of the joint prepared under optimum process parameters (i.e., at 1 000 ℃ for 60 min) can reach 86.7 MPa, and the fracture occurs in the weld nearby alumina ceramic base material.