Owing　to　its　good　welding　performance　and　lower　cost,　SAC0307　has　been　considered　as　one　of　the　most　promising　solders　to　replace　SnPb　alloy　and　become　popular　lead-free　solder　in　electronic　packaging　field.　However　the　reduction　of　silver　content　brought　some　problems　in　strength,　thermal　fatigue　behavior　and　creep　resistance　for　this　kind　of　joint　as　well.　Adding　filler　to　solder　matrix　so　as　to　form　the　composite　solder　is　a　common　method　to　improve　the　performance　of　solder.　Many　publications　indicated　that　the　addition　of　Polyhedral　oligomeric　silsesquioxane　(POSS)　improved　the　comprehensive　performance　of　Sn-based　lead-free　solders,　such　as　microhardness　and　thermostability.　In　this　study,　the　POSS-reinforced　SAC0307　solder　paste　was　made　by　using　the　mechanical　mixing　method.　Simple　shear　lap　Cu/SAC0307-xPOSS/Cu　joint　was　used　to　simulate　a　stress　state　as　a　real　solder　joint　suffered.　The　samples　were　tested　for　its　shear　strength　and　creep　rupture　life.　Besides,　microstructures　of　IMC　layer　of　as-reflowed　samples　and　SEM　fracture　surface　after　creep　test　were　also　examined　in　order　to　explain　the　reinforcement　effect　on　SAC0307　solder　alloy　by　adding　POSS　nano-particles.　©　2016　IEEE.