This　work　focused　on　the　electromigration　(EM)　behavior　of　the　Cu/Sn-58Bi/Cu　solder　joint　affected　by　the　large　void　formation.　The　as-reflowed　one-dimensional　solder　joint　was　stressed　with　current　density　of　5　x　10(3)　A/cm(2)　at　80　degrees　C　continuously　for　144h.　The　microstructural　evolution　was　observed　and　analyzed　by　SEM.　Results　indicated　that　the　abnormal　Sn/Bi　phase　segregation　was　observed　at　the　cathode　interface　of　the　solder　joint　owing　to　the　early　serious　defects　formation.　Local　current　flow　was　aggregated　surrounding　the　large　void,　resulting　in　the　Joule　heating　accumulation　there.　Therefore,　the　original　straight　direction　of　the　electrons　was　altered　near　the　void　region,　leading　to　the　unusual　Bi　migration.