In　order　to　reduce　the　error　in　strain　which　is　caused　by　the　digtial　image　correlation　method,　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.