Whisker　growth　in　Pb-free　solder　joints　is　one　of　the　most　reliability　concerns　in　electronic　industry.　Several　theories　and　models　were　developed　to　elaborate　whisker　growth,　and　many　attempts　were　made　to　find　solutions　to　solve　this　issue.　Micro　alloying,　such　as　introducing　Cu,　Bi,　Ag　etc.　into　solders,　is　considered　to　be　one　of　effective　method　to　mitigate　whisker　growth.　However,　when　alloying　with　these　metal　elements,　the　structure　of　solders　will　be　changed,　therefore　the　reliability　of　solders　needs　to　be　reevaluated.　The　purpose　of　this　research　is　to　explore　the　possibility　to　mitigate　whisker　growth　by　reinforce　strategy　without　destroying　the　structure　of　solders.　In　this　study,　a　novel　reinforcement,　nano-structured　cage-type　polyhedral　oligomeric　silsesquioxane　(POSS),　was　employed　and　expected　to　mitigate　whisker　growth.　FOSS　was　added　into　Sn,　Sn3.0Ag0.5Cu　and　Sn58Bi　solders　respectively.　Whisker　growth　behaviors　of　these　modified　solders　under　high　humidity　and　temperature　environment　(85　degrees　C,　85%　relative　humidity)　were　analyzed　and　discussed.　The　results　indicated　that,　the　driving　force　of　whisker　growth　was　compressive　stress　generated　by　the　volume　expanding　of　tin　oxides.　The　high　humidity　and　temperature　condition　facilitated　the　formation　of　tin　oxides　and　therefore　provided　continuous　driving　force　for　whisker　growth.　POSS　addition　could　inhibit　oxidation　process　of　metal　tin　effectively,　and　reduce　the　amount　of　tin　oxides　formation,　consequently　whisker　growth　was　mitigated.　Among　Sn,　Sn3.0Ag0.5Cu　and　Sn58Bi　solders,　Sn　solders　was　the　easiest　one　to　grow　whiskers,　while　Sn58Bi　was　at　the　lowest　risk　to　grow　whiskers.