The　safety　issues　related　to　explosion　venting　of　hydrogen-air　mixtures　are　significant　and　deserve　more　detailed　investigations.　Vented　hydrogen-air　explosion　has　been　studied　extensively　in　vessels　with　a　single　vent.　However,　little　attention　has　been　paid　to　the　cases　with　more　than　one　vent.　In　this　paper,　experiments　about　explosion　venting　of　rich　hydrogen-air　mixtures　were　conducted　in　a　small　cylindrical　vessel　with　two　symmetrical　vents　to　investigate　the　effect　of　vent　area　and　distribution　on　the　pressure　buildup　and　flame　behavior.　Experimental　results　show　that　venting　accelerates　the　flame　front　towards　the　vent　but　has　nearly　no　effect　on　the　opposite　side.　The　maximum　internal　overpressure　decreases　while　the　maximum　external　flame　length　increases　with　the　increase　of　the　vent　area.　Two　pressure　peaks　can　be　identified　outside　the　vessel,　which　correspond　to　the　external　explosion　and　the　following　gas　jet,　respectively.　Compared　with　the　case　of　single　vent,　the　use　of　two　vents　with　same　total　vent　area　leads　to　nearly　unchanged　maximum　internal　and　external　overpressure　but　much　smaller　external　flame　length.　©　2016　Hydrogen　Energy　Publications　LLC