Recently, the SiC chip for power devices had been developed to downsize the cooling system, because the operative temperature of SiC chip can be increase to over 300°C. However it is necessary to realize low temperature mounting and high reliability in high temperature. The author's group has proposed a new method using Ag-Nano material to mount the SiC chip on a Al board. The Ag-Nano can be mounted firmly on Al board with about 300°C, the stress relaxation facility can be given to the pure aluminum substrate side. In addition Ni plating was used as the final finish. As a result, Ni plating becomes as a new weak point. In this study, the authors proposed a new experimental method for investigating the reliability issues of the Ni plating in the Ag-Nano joint. Three point bending test is performed to evaluate the mechanical properties of Ni plating. A test specimen with Ni plating and a test specimen without plating in same size are prepared for a bend test, properties of Ni plating are calculated by comparing difference of those bend tests. And the fatigue strength was investigated by cyclic bending tests.