The　mixed　adsorption　of　a　cationic　gemini　surfactant,　ethanediyl-1,2-bis(dodecyldimethylammonium　bromide)　(abbreviated　as　12-2-12),　and　an　anionic　conventional　surfactant,　sodium　dodecyl　sulfate　(SDS),　was　examined　using　surface　tension　measurements.　The　viscoelastic　properties　of　the　mixed　films　were　investigated　by　dilational　interfacial　rheology　technique.　The　results　showed　that　the　addition　of　SDS　promoted　the　close　packing　of　adsorbed　molecules　at　the　interface,　which　increased　the　dilational　elasticity　of　the　mixed　films.　The　stability　of　the　foams　was　determined　by　the　half-life　of　foam　height　collapse.　The　foams　generated　by　12-2-12/SDS　mixtures　were　more　stable　than　that　formed　by　pure　12-2-12.　In　the　presence　of　sodium　bromide,　the　foam　stability　was　further　enhanced　and　the　surfactant　concentration　required　to　attain　the　maximum　effect　in　stabilizing　foams　was　greatly　reduced.　The　high　foam　stability　could　well　relate　to　the　high　elasticity　of　the　film.