A　new　product　modeling　method　for　product　multidisciplinary　collaborative　design　(MCD)　is　put　forward.　The　method　uses　a　flexible　product　model　which　can　be　extended　transversely　and　lengthwise　by　multiple　levels＇　inheritance　and　new　attribute　classes＇　addition　and　a　class　inheritance　mechanism　under　network　environment　which　allows　each　discipline　to　build　own　view　model　of　a　product.　An　open　and　flexible　system　architecture　supporting　the　product　MCD　effectively　is　put　forward,　and　prototype　system　implementation　is　introduced.