Dome　structures　have　been　used　extensively　for　industrial,residential,and　military　infrastructure.Therefore,it　is　necessary　to　understand　the　damage　risk　potential　for　such　structures　for　blast-resistant　design　considerations.This　paper　investigates　the　effect　of　blast　load　variability　on　the　design　value　and　the　structural　dynamic　response.Therefore,the　sources　of　uncertainty　in　the　external　blast　load　on　dome　structures　were　discussed　firstly.Then　based　on　the　probabilistic　blast　load　model　for　the　dome,the　rationality　of　a　deterministic　mass-increase　safety　method　was　assessed.It　was　found　that　previous　deterministic　design　method　cannot　provide　a　consistent　and　sound　assurance　factor　or　reliability　index　on　the　entire　dome　roof.In　addition,it　was　also　proved　that　the　assurance-based　load　method　fails　to　ensure　compliance　with　structural　safety　design　standards　on　the　dome　roof　when　compared　with　the　reliability-based　blast　method.A　sensitivity　analysis　on　the　probabilistic　blast　load　was　conducted,and　the　results　indicate　that　stand-off　distance　and　explosive　mass　both　act　as　dominant　sources　to　influence　the　mean　and　variability　of　blast　load.Therefore,based　on　the　Latin　hypercube　sampling　method,a　reliability-based　external　blast　load　factor　technique　was　proposed.This　technique　was　further　used　to　estimate　structural　damage　levels　of　a　single-layer　reticulated　dome　under　different　reliability　re-quirements,associated　with　a　low,medium,and　high　level　of　protection　grades　for　a　specific　explosion　scenario,and　it　indicated　that　this　technique　can　be　useful　in　the　building　design　to　achieve　a　higher　structural　anti-explosion　capacity.This　study　herein　can　serve　as　a　reference　for　the　calculation　method　of　designed　blast　load.