With　the　introduction　of　relevant　laws　and　regulations　in　many　countries,　the　electronic　industry　around　the　global　has　switched　into　lead-free　age　because　of　the　harm　of　lead　in　solder　on　the　environment　and　human　health,.　SnAgCu　based　solder　is　the　most　popular　lead-free　solder　recently.　The　solder　joint　reliability　has　become　an　increasingly　problem　due　to　the　change　of　packaging　materials　and　packaging　process.　In　this　study,　the　drop　reliability　of　lead-free　solder　joint,　including　Sn3.0Ag0.5Cu　(SAC305),　Sn1.0Ag0.5Cu　(SAC105)　and　Sn0.3Ag0.7Cu　(SAC0307)　was　studied.　It　can　be　seen　that　with　the　Ag　content　increasing,　the　thickness　of　the　intermetallic　compound　layer　increased.　Meanwhile,　the　intermetallic　compound　particles　inside　the　solder　become　smaller　and　the　number　of　particles　has　increased.　Thus　with　the　Ag　content　increasing,　the　tensile　strength　of　solder　joint　could　be　improved.　Under　dropping　load,　all　the　fracture　surfaces　are　relatively　bright　and　smooth.　That　meant　that　all　the　fracture　of　solder　joints　was　brittle.　With　the　Ag　content　increasing,　the　impact　performance　was:　SAC0307＞SAC105＞SAC305.