A　design　method　named　the　visualization　design　method　for　master　gears　is　introduced　to　improve　the　efficiency　of　master　gear　design.　The　method　is　based　on　the　theory　of　conjugate　surface　of　gears.　By　means　of　direct　numerical　simulation,　master　gears　can　be　designed　by　simulation　of　gear　cutting　processing.　Compared　with　the　formula　calculation　method,　the　advantages　of　the　visualization　design　method　are　visual　and　simple.　It　can　be　a　direct　design　method.