This　paper　reports　a　highly　stable　foam　system　generated　by　the　gemini　surfactant　ethanediyl-α,　ω-bis(tetradecyldimethylammonium　bromide)　(referred　to　as　14-2-14).　The　time　measured　for　the　collapse　of　the　foam　to　half　its　initial　height　was　used　to　characterize　the　foam　stability;　it　was　as　high　as　961　min　for　this　system　and　significantly　longer　than　that　(754　min)　for　ethanediyl-α,　ω-bis(dodecyldimethylammonium　bromide)　(12-2-12)　foams.　Thus　the　gemini　surfactant　structure　of　a　short　spacer　together　with　two　long　tails　enabled　it　to　be　a　highly　efficient　foam　stabilizer.　The　dilational　rheology　of　the　adsorbed　films　revealed　the　relationship　between　the　interfacial　elasticity　and　the　foam　stability.　The　high-frequency　limit　of　elasticity　of　the　adsorbed　film　at　a　specific　surface　coverage　was　again　found　to　indicate　foam　stability.　A　larger　limit　of　elasticity　indicated　a　more　stable　foam.©　Editorial　office　of　Acta　Physico-Chimica　Sinica.