Twokindsofgaseswereusedtoinvestigatetheinfluenceofgasdensityonthehydrodynamiccharacteristicsinabubblecolumn.Itcanbefoundoutthathighergasdensityleadstosmallerbubblediameterandtheflowpatternsaredifferentforthebothgases.Energybalancemechanismsareanalyzedbyconsideringthegasdensitydifference.Modelsweredevelopedtopredicttheaveragebubblediameterwithgoodaccuracy.