This　study　proposes　a　double-crown　tooth　surface　modification　technology　that　improves　the　load-carrying　capacity　of　non-orthogonal　helical　tooth　surface　gears.　The　tooth　modification　is　determined　by　a　modified　rack-cutter,　and　its　feed　motion　is　related　to　an　intentionally　designed　transmission　error.　The　novelty　of　the　tooth　modification　design　is　that　the　transmission　error　can　be　pre-designed.　First,　changing　the　tooth　profile　of　the　tool　enables　preliminary　modification　along　the　tooth　profile　direction;　second,　by　modifying　the　interaction　between　the　tool　and　the　machined　gear,　subsequent　fine　adjustments　are　made　to　the　contact　path.　This　two-stage　tooth　modification　strategy　not　only　retains　the　advantages　of　the　traditional　method　but　also　significantly　improves　the　balance　of　the　load　distribution　on　the　tooth　surface　through　an　original　contact　path　modification　strategy.　Through　systematic　tooth　contact　analysis　(TCA)　and　loaded　tooth　contact　analysis　(LTCA),　it　was　verified　that　the　new　method　reduces　contact　stress　and　tooth　root　bending　stress　and　improves　the　gear＇s　resistance　to　misalignment　errors.　This　research　provides　the　basis　and　motivation　for　further　exploring　and　improving　this　tooth　profile　modification　technology　to　solve　the　challenges　faced　by　more　complex　gear　systems.