An　identification　model　of　rotation　axis　basic　geometric　errors　was　derived　based　on　the　theory　of　homogeneous　transformation,　and　then　a　new　fast　measurement　method　and　identification　of　rotation　axis　basic　geometric　errors　based　on　ball-bar　were　proposed　herein.　The　measurement　of　ball-bar　was　adopted　by　one　end　of　the　ball　-bar　was　fixed　on　the　rotary　table　in　three　different　positions　respectively.　By　the　linkage　control　the　other　end　of　the　ball-bar　in　circular　trajectory,　the　deviations　of　each　position　measurement　point　in　the　directions　of　X,　Y　and　Z　could　be　measured　in　each　discrete　position.　And　then　the　rotation　axis　six　basic　geometric　errors　could　be　identified　according　to　the　established　identification　model.　As　to　guide　the　distribution　of　the　measuring　points　and　reduce　the　influence　of　measurement　error,　a　method　based　on　sensitivity　analysis　of　the　coefficient　matrix　was　presented　and　the　accuracy　of　error　identification　is　improved.