The bonding strength decay law of three kinds of gold wire of 18, 25, 30 μm, and aluminum wire of 25, 32, 45 μm under different temperature cycles, as well as the ratio of the breaking mode were studied. The results show that, all test samples, regardless of whether they undergo temperature cycles, have reached the minimum bond strength requirement of GJB548B-2005, and there is no puff-off mode. As the times of temperature cycles increase, the bonding strength of the gold wire increases slightly at first, then slowly decreases and tends to level off. Meanwhile, the bonding strength of aluminum wire decreases rapidly first, then decreases slowly, and tends to be gentle. Compared with gold wire, the bonding strength of aluminum wire decays faster under temperature cycles of 0 to 50 times. The article also obtains the bond strength attenuation change equation under different wire diameters through curve fitting.