Abstract:This article summarizes the types and properties of Cu-Ni-Si alloys used for lead frames in recent years, and the correlated strengthening mechanisms. Special attentions are paid to summary the relationship between the mechanical properties and electrical conductivity of the alloys and the contents of Ni, Si as well as the addition of different trace elements. Meanwhile, the development status of copper-nickel-silicon alloy preparation process and forming technology is briefly introduced. It is prospected that the performance of Cu-Ni-Si alloy should satisfy the strength of 750~840 MPa and the conductivity of 35% IACS in the future. And,its preparation technology will develop towards the direction featured with high-tech integration, large-scale fabrication, and green manufacturing concept.