There　are　obvious　differences　in　shape　and　space　between　the　large-span　spatial　structure　and　the　traditional　steel　structure,　and　there　will　be　openings　at　the　top　of　the　spatial　structure.　However,　there　are　few　studies　on　the　fire　of　the　spherical　dome　large　space　building　with　openings　at　the　top,　which　makes　the　classical　plume　model　inapplicable.　The　axial　temperature　of　the　plume　centerline　predicted　by　the　traditional　plume　model　is　quite　different　from　the　real　results.　Therefore,　this　paper　investigates　the　temperature　dynamics　within　large-span　spatial　structures　during　large-scale　fire　scenarios,　utilizing　a　combination　of　theoretical　analysis　and　finite　element　numerical　simulations.　It　meticulously　assesses　how　different　natural　ventilation　inlet　areas　affect　both　the　smoke　exhaust　capacity　and　the　temperature　field　distribution　within　these　structures.　The　research　expands　on　the　traditional　plume　model　by　introducing　an　enhanced　formula　for　calculating　the　plume　center　velocity,　specifically　designed　for　large-span　structures　with　top　openings.　Additionally,　using　an　improved　two-region　model,　the　paper　derives　a　logarithmic　model　that　describes　the　temperature　variation　as　a　function　of　vertical　height　within　the　structure.　This　theoretical　model　is　then　compared　with　numerical　simulation　results.　The　study　finds　that　increasing　the　natural　ventilation　inlet　area　significantly　enhances　the　efficiency　of　smoke　exhaust　and　reduces　temperatures　within　the　fire　smoke　layer　of　large-span　spatial　structures.　The　derived　temperature　logarithmic　curve　model　shows　high　precision　in　predicting　the　spatial　temperature　distribution　after　the　fire　reaches　a　quasi-steady　state,　with　an　average　relative　error　of　6%　between　predicted　and　simulated　temperatures,　confirming　its　accuracy.　The　conclusion　is　of　great　significance　to　the　study　of　fire　smoke　movement　in　large-span　spatial　structures.　The　obtained　logarithmic　curve　model　of　temperature　under　fire　provides　an　important　basis　for　the　fire　protection　design　of　spherical　dome　spatial　structures　under　natural　smoke　exhaust.