Based　on　a　tooth　profile　equation　for　DIN　standard　ZK　type　worm　gears,　a　mathematical　model　of　tooth　profile　measurement　errors　was　established.　Given　the　worm　parameters,　error　measuring　the　tooth　profile,　or　fz,　is　the　function　of　probe　offset　value　y0.　A　curve　for　tooth　profile　measuring　error　was　derived　and　its　properties　were　studied.　At　the　same　time,　the　influence　of　the　probe＇s　offset　on　tooth　profile　measuring　error　was　analyzed,　using　different　modules,　numbers　of　threads,　and　pitch　circle　diameters.　According　to　the　principles　determining　device　precision,　the　maximal　probe　offset　value　was　defined　by　precision　of　worm　measurement.　Finally,　the　principle　error　in　a　tooth　profile＇s　approximate　measurement　was　analyzed,　and　an　example　was　given　to　explain　the　feasibility　of　improving　a　tooth　profile＇s　approximate　measurement.　The　study　can　provide　guidance　for　more　precise　measurements　of　the　tooth　profiles　of　ZK　type　worm　gears.