Electromigration　could　induce　the　movement　of　atoms/ions　towards　the　direction　of　electron　flow　in　pure　metal　line　in　chips.　However,　in　the　eutectic　SnBi　solder　joints,　the　constituted　elements　are　Sn　and　Bi.　Due　to　the　different　drift　velocity　of　Bi　atoms　and　Sn　atoms　under　high　current　density,　the　electromigration　properties　of　eutectic　SnBi　are　unique.　With　a　current　density　of　104A/cm2　and　the　Joule　heating　effect,　the　temperature　of　solder　joints　increased　from　25　to　50C,　and　the　Bi-rich　phases　grew　bigger　during　current　stressing　due　to　the　high　ambient　temperature　(49C).　In　addition,　Bi　atoms　initially　arrived　at　the　anode　side　and　eventually　formed　a　barrier　layer　to　inhibit　the　movement　of　Sn　atoms　towards　the　anode　side.　Sn-rich　phase　bulged,　and　a　valley　formed　along　the　interface　at　cathode　side.