The　adsorption　of　O-2　molecules　and　O　atoms　on　the　CuCl(111)　surface　was　studied　using　first-principle　calculations　based　on　the　density　functional　theory　with　the　generalized　gradient　approximation　developed　by　Perdew　and　Wang　(PW91).　Adsorption　models　under　different　coverages　of　the　CuCl(111)　surface　were　considered.　The　adsorption　over　various　adsorption　sites　(top-V,　hollow-VI　bridge-V,　Cl-V,　top-P,　hollow-P,　bridge-P,　and　Cl-P　sites)　was　selected　for　calculation.　The　optimized　results　indicated　that　the　adsorption　was　very　stable　when　the　coverage　was　set　to　0.25　monolayer.　The　O-2　molecule　was　inclined　to　adsorb　aslant　on　the　CuCl(111)　surface,　and　the　O-O　stretching　vibrational　frequencies　were　significantly　red-shifted.　The　results　of　the　Mulliken　population　analysis　and　the　density　of　states　indicated　that　the　charges　transferred　from　Cu　to　oxygen.　The　O　atom　was　likely　to　adsorb　at　the　hollow　site　of　the　CuCl(111)　surface.　The　Mulliken　population　analysis　and　the　density　of　states　were　calculated　to　explain　the　computed　results.