Compared　with　contact　measurement,　machine　vision　inspection,　a　noncontact　measurement,　has　the　advantages　of　high　efficiency,　complete　information,　good　stability,　and　recognizable　defects.　It　has　been　used　increasingly　in　the　field　of　gear　inspection.　Many　gear　inspection　instruments　based　on　machine　vision　technology　have　been　developed　in　the　last　10　years,　including　video　measuring　machines,　flash　measuring　machines,　CVGM　instruments,　and　online　inspection　equipments　that　can　perform　both　comprehensive　gear　inspection　and　analytical　gear　measurement.　This　paper　examines　the　development　processes　and　characteristics　of　gear　visual　inspection　instruments;　analyzes　the　research　and　application　progress　of　algorithms　such　as　edge　detection,　subpixel　positioning,　feature　extraction,　and　pattern　recognition　in　gear　visual　inspection;　summarizes　the　technical　development　of　machine　vision　in　gear　accuracy　measurement　and　gear　defect　inspection;　and　identifies　the　future　development　prospects　of　gear　visual　inspection　instruments　and　technology.