The　adsorption　of　N2　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　was　N2　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　2π　antibonding　orbitals　of　N2　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.　©　Editorial　office　of　Acta　Physico-Chimica　Sinica.