In this study, an attempt to investigate a coupling modification method for grain refinement in Zn-Sn-Cu-Bi (ZSCB) high-temperature solder has been made. During coupling modification, primary grains nucleated from CeZn5 sites and grew to form much more ε-CuZn5 phases compared with the original solder. Peritectic η-Zn phases were also refined, transformed from matrix to equiaxed phases, with grain size of 1.40–2.24µm and uniform elements distribution was achieved. By means of coupling modification, the mechanical properties of ZSCB high-temperature solder, the tensile strength and elongation, show indeed significantly improvement with an increase of 77.15% and 112.68%, respectively.