Deformation　measurement　of　solder　joints　under　various　loadings　such　thermal　and　drop/impact　is　important　in　reliability　design　of　electronic　packages.　It　is　difficult　to　use　traditional　techniques　such　as　strain　gage　method　to　measure　the　strain　of　solder　joints　because　of　their　small　sizes.　Instead,　the　digital　image　correlation　method　(DICM)　is　applied　to　catch　the　deformation　of　the　solder　joints.　The　discrete　displacement　obtained　by　the　digital　image　correlation　method　does　not　satisfy　the　deformation　compatibility,　as　a　result　the　error　in　strain　which　is　calculated　by　deriving　the　displacement　is　enlarged.　In　order　to　reduce　the　error,　an　approach　is　proposed　in　which　a　continuous　displacement　field　is　constructed　firstly　to　fit　the　discrete　measure　points　by　the　technique　used　in　the　finite　element　method　and　the　least　square　method,　then　the　strain　is　calculated　from　the　continuous　displacement　field.　The　results　indicate　that　error　in　displacement　and　strain　can　be　significantly　reduced　by　the　proposed　approach.　©2007　IEEE.