As　the　key　parts　of　a　toroidal　drive　the　tooth　surfaces　of　the　sun-worm　and　the　stationary　internal　toroidal　gear　were　complex　space　curved　surfaces.　The　accurate　entity　model　of　the　sun-worm　and　the　stationary　internal　toroidal　gear　had　direct　influences　on　the　precision　of　the　NC　machining.　Aiming　at　the　sun-worm　digital　modeling　problems,　according　to　the　mathematical　model　of　the　sun-worm,　the　grid　division　method　of　the　helical　tooth　surface　was　given,　the　method　of　the　toroidal　drive　accurate　entity　modeling　based　on　tooth　surface　grid　was　put　forward　and　was　verified　by　NC　machining.