Combinatorial　auctions　can　be　used　to　reach　efficient　resource　and　task　allocations　in　multi-agent　system　where　the　items　are　complementary　or　substitutable.　Determining　the　winners　is　NP-complete.　This　paper　presents　a　negotiation　model　which　is　based　on　the　nuilti-agent,　and　gives　the　basic　characteristics　and　the　satisfied　conditions　of　winner　determination　which　is　determined　by　the　solution　of　Nash　negotiation　and　indicate　the　rationality　and　fairness　of　this　method　based　on　the　analysis　about　the　utility　increment　of　the　bid　agent　and　the　benefit　increment　of　the　auction　agent.