In this paper, the impact properties of viscoplastic Pb-free solder based Sn-Ag have been studied by means of a split Hopkinson pressure bar (SHPB) at various strain rates. The tests were conducted at room temperature and under uniaxial compressive conditions. It is found that the materials' dynamic flow stress and yield stress dramatically increase relation to the strain rate. The temperature rise during high strain rate deformation is analyzed, and results indicate it has less impact to dynamic yield stress. The dynamic mechanical prosperities and the effect of strain-rate of lead-free solder discussed show that Sn-Ag solder is attractive to the electronic industry.