FZG　gear　testing　is　widely　used　to　evaluate　the　performance　of　lubricants,　gear　materials,　and　gear-tooth　geometries　under　different　loads.　During　these　tests,　gear　tooth　wear　results　in　the　loss　of　gear　profile　in　the　form　of　micro-pitting,　pitting　and　scuffing,　can　be　observed.　However,　gear　wear　is　usually　measured　by　weighting.　This　method　cannot　be　used　to　study　the　wear　depth　on　a　specific　point　on　the　gear-tooth　surface.　In　this　study,　tooth　profiles　were　measured　via　a　profilometer　during　the　FZG　gear-pitting　test.　Moreover,　an　algorithm　was　developed　to　quantitatively　evaluate　the　distributed　cumulative　wear　and　wear　progress　at　a　certain　test　stage.　Simultaneously,　the　real　tooth　profile　was　obtained.　Experiments　were　performed　to　validate　the　proposed　method,　and　the　results　showed　that　gear-tooth-surface　wear　can　be　quantitatively　determined.　Thus,　the　proposed　method　can　be　used　for　further　gear-failure-prediction　experiments.　©　2020