In　this　paper,　the　grain　orientation　evolution　of　Sn3.0Ag0.5Cu　ball　grid　array　(BGA)　solder　joints　under　thermomechanical　stress　was　characterized　quantitatively　using　electron　backscatter　diffraction　(EBSD).　Further　polishing　of　the　cross-sections　of　as-reflowed　solder　joints　was　avoided　after　thermal　shock　treatment　to　accurately　analyze　the　underlying　recrystallization　mechanism　(no　previous　reports　on　this　topic　exist　because　of　the　inability　of　pattern　indexing　due　to　cross-section　contamination　after　thermomechanical　fatigue).　The　results　showed　that　subgrains　appeared　before　the　formation　of　recrystal-lized　grains　in　Pb-free　solder　joints　under　thermomechanical　stress,　and　the　orientations　of　the　small　recrystallized　grains　separated　by　high-angle　grain　boundaries　evolved　from　the　initial　orientations　via　subgrain　rotation.　The　localized　recrystallization　produced　fine　grains　and　grain　boundary　sliding　in　the　solder　joints　during　thermal　shock　treatment.　Additionally,　slip　systems　played　an　important　role　in　recrystallization　and　could　be　used　to　predict　the　subgrain　and　recrystallized　grain　formation.　Avoiding　further　polishing　of　the　cross-sections　of　as-reflowed　solder　joints　during　thermal　shock　treatment　is　an　effective　method　to　accurately　investigate　the　recrystallization　behavior　and　grain　orientation　evolution　(as　a　function　of　the　subgrain　and　recrystallized　grain　rotation　behavior)　of　Pb-free　solder　joints.　(C)　2016　Elsevier　B.V.　All　rights　reserved.