In　order　to　solve　the　problems　in　existing　methods　for　blade　profile　metrology,　such　as　low　accuracy　and　efficiency,　poor　flexibility,　various　constraints,　a　high-precision　form-free　method　for　blade　profile　metrology　is　proposed.　In　the　paper,　the　operational　principle,　key　technologies　and　evaluation　methodology　are　analyzed　in　detail.　A　high-precision　method　for　blade　profile　metrology　based　on　the　concept　of　＂Synchronization　of　Planning　and　Measurement＂　is　proposed　to　solve　three　key　problems　for　blade　metrology　synchronously:　theoretical　data　acquisition,　path　planning　and　sampling　strategy　analysis,　and　profile　measurement.　A　form-free　evaluation　methodology　for　blade　profile　based　on　parametric　modeling　is　also　discussed.　The　results　show　that　the　metrology　and　evaluation　for　blade　profile　are　executed　automatically　without　theoretical　model　data,　thus　improving　the　efficiency　and　flexibility　greatly.　In　addition,　all　the　measurements　are　completed　in　the　positions　near　the　reference　distance　of　the　sensor,　thus　the　depth　of　measurement　approaches　0　mm　and　the　measurement　error　is　no　more　than　10　mu　m.　The　method　proposed　in　the　paper　is　a　form-free　method　with　a　high　precision　and　has　a　good　application　prospect　in　the　field　of　free-form　surface　measurement.　[GRAPHICS]　.