A series of Ni-Cu/ZnO catalysts were prepared and studied by temperature-programmed reduction. The results show that after reduction a Ni-Cu alloy formed; the strength of Ni-Cu interaction depends on the Ni-Cu ratios, the higher the Cu/Ni ratio, the stronger the Ni-Cu interaction. This phenomenon was attributed to the donation of electrons from the d band of Cu to that of Ni, increasing the bonding strength.