Thispapercarriesoutabinitiocalculationstostudythe80Se2(X3Σg-)stateand80Se2(X2Πg),80Se2(a4Πg)statesbyusingcompletedactivespaceself-consistentfieldandmulti-referencesecondorderperturbationtheory.Theelectroniccurvesofthesestatesincludingspin-orbitcouplingarecalculated,andthenthespectroscopicparametersareobtained.Thephotoelectronspectraof80Se2moleculeingasphaseareassignedaccordingtoFranck-Condonanalysisbasedoncalculatedpotentialenergycurves.Theionizationenergiesof80Se2moleculearedeterminedbythepresentcalculation.