This　study　proposes　a　model　for　the　quantitative　evaluation　of　the　life-cycle　carbon　footprints　of　large　sporting　events　and　the　uncertainties　related　to　them.　The　model　was　used　to　analyze　the　case　of　a　mega　sporting　event　in　Beijing,　China.　First,　the　quantitative　model　for　the　evaluation　of　the　carbon　footprints　of　mega　sporting　events　includes　a　preparation　stage,　a　holding　stage,　and　an　end　stage.　These　stages　consider　the　energy　and　resources　used　for　construction,　operation,　transportation,　catering,　and　accommodation.　Second,　this　study　proposes　a　prediction　model　using　model-based　and　simulation-based　methods　to　address　the　difficulty　of　obtaining　traffic　activity.　Third,　a　semi-quantitative　method　that　combines　a　data　quality　indicator　and　stochastic　simulation　is　adopted　for　the　uncertainty　analysis　of　mega　sporting　events.　Finally,　a　case　study　is　used　to　indicate　that　the　preparation　stage　of　a　mega　sporting　event　accounts　for　the　highest　CO2　emissions　at　92.1%,　followed　by　7.5%　in　the　holding　stage　and　0.4%　in　the　end　stage.　The　total　life-cycle　CO2　emissions　of　a　sustainable　scenario　of　a　mega　sporting　event　in　Beijing　amount　to　205,080.3　t　CO2e,　and　the　per　capita　CO2　emissions　during　the　event＇s　holding　stage　amount　to　0.26　t　CO2e/person.　The　uncertainty　in　the　input　parameters　is　0.0617,　indicating　that　the　uncertainty　of　the　model　is　low,　and　the　reliability　of　the　results　is　high.