Traditional　SIFT　method　has　certain　false　matching　points　and　will　miss　a　large　number　of　correct　matching　points　in　image　registration　process.　To　solve　this　problem,　an　improved　SIFT　algorithm　based　on　scale,　orientation　and　distance　constraint　(SODC-SIFT)　is　proposed　in　this　paper.　First,　the　images　are　matched　with　original　SIFT　algorithm,　and　the　scale　and　orientation　joint　restriction　are　used　to　remove　mismatching　pairs.　Then,　the　least　square　method　is　employed　to　calculate　the　geometric　relationship　between　the　two　images.　Finally,　iteration　is　conducted　to　select　the　correct　matching　points　by　distance　constraint,　so　as　to　achieve　accurate　image　registration.　Experimental　results　show　that　the　proposed　method　has　greater　robustness　and　achieves　more　correct　matching　pairs　than　the　traditional　SIFT　method.　Furthermore,　the　correct　matching　rate　is　increased　and　the　accuracy　of　the　algorithm　is　enhanced.　©　2017,　Editorial　Office　of　Nanotechnology　and　Precision　Engineering.　All　right　reserved.