The Sn-Pb alloy plating is mainly used for an electronic material now. However, there is a problem that Pb pollutes the environment. Therefore, Sn-Pb alloys are principally prohibited using in the electronic component with the RoHS instruction. Therefore, an alternative material of Pb is called upon now. However, whisker generation have been problem when an alternative material of Sn-Pb alloy is used. Therefore in this study, various investigations are conducted to prevent whisker generation when an alternative material of Pb is used on the basis of microstructure control for best plating material.