At　present,　RC　utility　tunnels　are　widely　used　in　urban　utility　tunnels.　As　a　typical　confined　space,　the　complex　load　effect　generated　by　the　internal　gas　explosion　of　the　gas　tank　of　utility　tunnel　may　lead　to　local　damage　or　overall　destruction　of　the　structure　of　RC　utility　tunnel.　Therefore,　it　is　an　important　topic　to　improve　the　anti-explosion　capability　of　the　utility　tunnel　and　ensure　the　normal　operation　of　the　utility　tunnel　after　gas　explosion.　UHPC　structure　is　considered　to　have　excellent　anti-explosion　performance,　so　a　ribbed　thin-walled　UHPC　utility　tunnel　structure　was　proposed,　which　improved　the　overall　stiffness　and　anti-explosion　performance　of　the　UHPC　utility　tunnel　through　the　ribbed　section.　In　view　of　the　shortcomings　of　fluid-solid　coupling　method　in　gas　simulation,　Computational　Fluid　Dynamics　(CFD)　was　used　to　calculate　the　overpressure　distribution　after　gas　explosion　in　UHPC　utility　tunnel.　The　accuracy　of　UHPC　constitutive　model　and　prestress　simulation　method　was　verified　by　testing　results　from　the　gas　explosion　on　unbonded　prestressed　UHPC　slab.　The　gas　explosion　damage　mechanism　of　ribbed　thin-walled　UHPC　utility　tunnel,　UHPC-NC　combined　utility　tunnel　and　RC　utility　tunnel　were　comparatively　analyzed.　And　the　pre-fabricated　stiffener　height,　UHPC　slab　thickness　and　UHPC　strength　were　investigated　on　the　anti-explosion　performance　of　ribbed　thin-walled　UHPC　utility　tunnel　against　gas　explosion.　It　is　found　that　the　UHPC　strength　needs　to　be　enhanced　dramatically　to　improve　the　blast　resistance.　The　anti-explosion　capability　of　utility　tunnel　can　be　effectively　increased　by　increasing　the　rib　height　or　increasing　the　thickness　of　the　UHPC　utility　tunnel　structure,　and　the　damage　pattern　of　the　utility　tunnel　can　also　be　changed　from　flexureshear　failure　to　bending　failure.　The　results　of　the　study　can　provide　a　reference　for　the　damage　analysis　and　anti-explosion　design　of　ribbed　thin-walled　UHPC　utility　tunnels.