The　adsorption　of　N-2　molecule　on　the　UO(100)　surface　was　studied　with　periodic　slab　model　by　VWN-BP　approach　of　GGA　within　the　framework　of　density　functional　theory　(DFT).　The　results　of　geometry　optimization　indicated　that　the　most　stable　structure　of　adsorption　wits　N-2　adsorbed　parallelly　on　the　hollow　site　with　an　adsorption　energy　of　79.0　kJ.mol(-1).　The　analysis　of　Mulliken　population　and　density　of　states　indicated　that　2　pi　antibonding　orbitals　of　N-2　molecules　got　electrons　from　d　and　f　orbitals　in　uranium.　The　vibration　wave　number　of　N-N　range　from　1770　to　2143　cm(-1).　Complete　linear　synchronous　transit　(LST)　and　quadratic　synchronous　transit　(QST)　were　used　to　search　the　transition　state　for　dissociation　reaction.　The　predicted　lowest　energy　barrier　was　266.9　kJ.mol(-1).