Line　laser　3D　measurement　of　gears　(LL3DMG)　is　a　critical　technology　that　enables　the　rapid　acquisition　of　full　3D　tooth　surface　data.　This　method　compensates　for　the　limitations　of　traditional　measurement　techniques,　which　rely　on　a　limited　number　of　points　and　lines　on　the　tooth　surface　and　involve　small　sample　data　processing　methods　in　gear　inspection.　Instead,　it　truly　reflects　the　complex　3D　topography　of　the　tooth　surface,　including　the　size　and　modification　of　gears.　This　article　provides　a　summary　and　analysis　of　the　main　manufacturers　of　line　laser　sensors　(LLSs),　emphasizing　their　distinct　designs　and　features.　It　also　reveals　the　prominent　role　and　developmental　trends　of　LLSs　in　contemporary　intelligent　manufacturing　sectors.　Furthermore,　based　on　different　application　scenarios　and　equipped　devices,　a　comprehensive　analysis　and　comparison　of　six　different　solutions,　as　well　as　our　team＇s　solution,　were　conducted.　Each　solution　exhibited　unique　advantages.　This　further　elaborates　on　the　research　status　and　development　trends　of　LL3DMG-related　technologies.　This　article　also　introduces　the　key　methodological　elements,　such　as　the　optical　characteristics　of　the　LLSs,　pose　parameter　calibration,　measurement　pose　characteristics,　and　3D　measurement　data　preprocessing　in　LL3DMG,　along　with　possible　solutions.　Additionally,　the　challenges　associated　with　LL3DMG　are　summarized　and　analyzed,　and　future　research　prospects　for　LL3DMG　are　analyzed　in　five　main　aspects:　(1)　enhancing　and　ensuring　measurement　accuracy,　(2)　combining　intelligence　for　effective　fusion　and　applications,　(3)　exploiting　and　utilizing　big　data　on　gear　surfaces　at　depth,　(4)　facilitating　miniaturization　and　portability　of　sensors　and　integration　and　networking　of　system,　and　(5)　establishing　a　gear　measurement　cloud　platform.　In　summary,　these　advancements　also　will　present　fresh　opportunities　for　the　LL3DMG　and　related　fields　to　develop　innovative　technologies　and　products　that　cater　to　a　wide　range　of　applications.　©　2024　Elsevier　Inc.