A　set　of　customized　CAD　application　system　based　on　GMDH　method　for　racing　bike　frame　is　developed　by　summarizing　the　characteristics　of　man-machine　engineering　principle　and　bike　sports,　taking　self-organizing　data　mining　method　of　using　Group　Method　of　Data　Handling　(GMDH)　as　well　as　AutoCAD　as　platform.　The　system　with　functions　of　customized　design　of　bike,　parametric　design　drawing　and　rapid　automatic　modeling　improves　the　design　level　and　efficiency　of　bike　frame.