In　this　paper,　soldered　lap　joint　specimens　were　fabricated　by　a　solder　reflow　process　using　a　Sn-3.8Ag-0.7Cu-xRE　(x=0,　0.1wt%,　0.25wt%,　0.5wt%)　BGA　solder　ball　on　FR4　substrate　parts.　The　effects　of　rare　earth(RE)　content　and　strain　rate　on　the　shear　properties　of　soldered　lap　joint　were　investigated.　The　Results　show　that　the　addition　of　minute　RE　(＜0.25wt%)　can　improve　the　shear　strength　and　elongation　of　the　lap　joint.　However,　further　increasing　of　RE　content　would　degrade　the　shear　properties　of　the　lap　joint.　The　shear　strength　and　elongation　of　the　lap　joint　increase　with　the　increase　of　strain　rate.　The　analysis　of　the　microstructure　and　fractograph　indicated　that　through　the　addition　of　minute　RE,　the　microstructure　of　the　lap　joint　was　refined,　especially　the　growth　of　intermetallic　compound　was　inhibited,　and　thus　the　shear　properties　of　the　lap　joint　were　improved.　In　addition,　the　observation　of　fractographs　confirmed　that　the　elongation　of　the　lap　joint　increase　with　the　increase　of　strain　rate.