It has been known that the grain refinement of Cu base alloys greatly improved mechanical properties, castability, workability and hot shortness resistance etc. In this study CuZr50, CuP7, CuFe7, CuMg10 binary alloys were added as grain refiners in CuZn36 alloy. The alloys melted in vacuum and controlled in mixed gas conditions and casted at 1050℃. Zr-P-X compound has significantly grain refined but oxygen has been found detrimental to grain refinement. In the case of Zr/B ratio below 4, B acted as grain growth element in this alloy.