To　ensure　high-precision　calibration　of　gear　measuring　instruments,　the　international　standard　ISO/TR　10064-5:2005　recommends　a　Double-Ball　Artifact　(DBA)　as　calibration　reference.　The　DBA　employs　a　high-precision　sphere　to　replace　the　involute　and　uses　an　error　compensation　technique　to　obtain　a　high-precision　involute　to　realize　the　involate　traceability.　The　theoretical　issues　relating　to　the　DBA　are　discussed　to　provide　a　theoretical　basis　for　the　design　and　application　of　the　DBA.　The　error　of　measurement　principle　of　DBA　and　its　calculation　function　are　given　under　the　conditions　of　ideal　installation　and　with　installed　errors　for　the　electronic　generative　metrology.　According　to　the　optimized　arc　thoughts,　the　formula　of　the　optimized　center　distance　between　the　two　balls　is　derived　by　the　least　square　method.　Finally,　the　error　compensation　method　is　described.　The　DBA　software　is　designed　based　on　the　above　theory　and　a　DBA　is　developed　with　a　parameter　of　module　in　2.268　1　mm,　number　of　teeth　in　40,　and　a　pressure　angle　in　20°.