Copper alloy with no lead

This invention relates to a Pb-free Cu alloy, especially a Pb-free machinable Cu alloy, which is composed of: Cu 55.0-89%, Zn 3.0-45%, Sn 0.1-10%, Ni 0.1-2.0%, Si 0-5.0%, Bi 0.1-5.0%, Se 0-3.0%, Al 0.01-1.0%, P 0.05-0.15%, and RE 0.01-0.5%. RE, Bi, Se and P are added respectively in the forms of RE-Cu intermediate alloy, Cu-Bi intermediate alloy, Cu-Se intermediate alloy and P-Cu intermediate alloy, or RE, Bi, Se and P are added respectively in the forms of Bi-Se alloy and P-Cu alloy. This invention can eliminate harmful effects on environment and human bodies caused by Pb during production and recovery process. The Cu alloy has good machinability, mechanical properties, processability and fluidity, and has no thermal splitting. The production method is simple, and can produce the Cu alloy by using the present apparatus for producing lead-brass alloy. Besides, the contents of Se, Bi and RE are low,.