Rapidly　obtaining　the　three-dimensional　error　information　for　all　tooth　surfaces　of　gears　is　the　key　and　prerequisite　for　characterizing　the　quality　of　complex　tooth　surfaces.　In　this　paper,　based　on　the　principle　of　laser　triangulation,　a　three-dimensional　measurement　model　with　line　laser　is　established　for　the　gear,　and　the　developed　measuring　instrument　can　be　used　to　quickly　obtain　the　error　information　of　three-dimensional　tooth　surface　and　evaluate　the　quality　of　gear.　The　instrument　adopts　the　vertical　structure　consisting　of　base,　precision　spindle,　circular　grating　sensor,　control　system　and　software　system,　etc.　The　precision　spindle　adopts　the　dense　bead　shaft　system　to　achieve　high-precision　rotation,　which　ensures　the　high-precision　positioning　and　rotation　of　measured　gear.　Two　high-precision　line　laser　sensors　are　arranged　in　the　circumferential　direction　of　the　precision　spindle,　and　the　positional　state　is　adjusted　according　to　the　parameters　of　measured　gear.　Specifically,　the　rotation　angle　of　precision　spindle　is　acquired　by　the　circular　grating　in　real　time,　and　the　geometrical　information　of　gears’　left　and　right　flanks　is　collected　and　recorded　by　the　collector　in　real　time.　In　conclusion　the　three-dimensional　measurement　and　evaluation　software　for　the　gear　has　been　developed,　which　can　realize　the　measurement　and　evaluation　of　gear′　s　tooth　profile　deviation,　pitch　deviation,　topological　deviation　etc.,　and　meet　the　detection　requirements　of　grade　5　precision　gear.　©　2024　Science　Press.　All　rights　reserved.