Abstract: The mixed Sn and Cu powder was milled by mechanical ball milling.The milled powders were analyzed by X-ray diffraction,differential thermal analyzer and scanning electron microscope.The effect of ball milling conditions on the formation of Sn-0.7Cu alloy was investigated.The results showed that voltage,ball-to-powder mass ratio,and milling time affect the formation of Sn-0.7Cu alloy significantly.The mechanism of mechanical alloying Sn-Cu was that the mechanically-induced atom diffusion drives substitutional solid solution and interface dissolution,as a result of which Cu₆Sn₅ was formed.