Twice-shocked　interaction　phenomena　are　frequently　observed　in　engineering　in　scenarios　where　the　passageway　of　the　shock　wave　contains　obstacles.　In　this　work,　the　transient　droplet　deforma-tion　and　breakup　behaviors　induced　by　a　shock　wave　before　a　standing　wall　were　first　experimentally　recorded　using　a　high-speed　background　technique.　Special　attention　was　paid　to　the　effect　of　theWe-ber　number　(We)　on　the　evolution　process.　Four　dimensionless　droplet-wall　distances　(once　shocked:　L/d0　=　1;　twice　shocked:　L/d0　=　3,　1,　and　0.6)　were　involved,　along　with　We　ranging　from　50　to　16,770.　The　results　showed　that　compared　with　the　once-shocked　experiments,　the　deformation　and　breakup　behaviors　of　the　twice-shocked　experiments　varied　greatly　due　to　the　rather　complex　flow　conditions.　Many　new　deformation　and　breakup　features　such　as　a　hat　shape　and　multi-sheets　were　observed.　The　dimensionless　cross-stream　diameter　(dc/d0)　increased　over　time　for　all　cases,　while　the　oscillation　and　flat　disc　phenomena　appeared　in　some　twice-shocked　cases.　The　growth　rate　of　dc/d0　increased　with　the　We　in　both　the　once-and　twice-shocked　experiments.　Owing　to　the　accelerated　breakup　process,　with　an　increase　in　the　We　the　maximum　of　the　dimensionless　droplet　cross-stream　diameter　(dc/d0)max　decreased　in　the　once-shocked　experiments.　The　variation　trend　of　(dc/d0)max　varied　with　L/d0.　For　the　L/d0　=　3　cases,　the　value　of　(dc/d0)max　first　increased　and　then　decreased　with　the　We　since　the　increased　We　changed　the　breakup　behaviors.　For　the　L/d0　=　1　and　0.6　cases,　the　value　of　(dc/d0)max　increased　with　the　We　when　the　We　was　ele-vated　from　50　to　3592,　which　was　because　the　higherWe　cases　had　more　time　to　acquire　energy　from　the　outside.　For　the　twice-shocked　experiments,　the　droplets　oscillated　at　their　natural　frequency　for　different　values　of　L/d0　and　We.　©　2019　Begell　House　Inc..　All　rights　reserved.