Asymmetric　Gemini　surfactants　CmH2m+1OCH2CH(OH)CH2N+(CH3)2C8H17Br,　referred　to　as　CmOhpNC8　(m=10,　12　and　14),　were　synthesized.　This　type　of　surfactant　molecule　has　a　head　region　(a　hydroxyl　and　a　quaternary　ammonium　linked　by　one　methylene　group)　with　a　small　size　and　two　alkyl　chains　with　different　lengths.　The　maximum　bubble　pressure　technique　was　used　to　investigate　the　adsorption　kinetics　of　CmOhpNC8　aqueous　solution　below　their　critical　micelle　concentrations　at　the　air/water　interface.　The　results　showed　an　obvious　kinetic　process　for　the　adsorption　of　CmOhpNC8.　When　CmOhpNC8　were　adsorbed　on　the　freshly　formed　interface,　the　adsorption　process　was　pure　diffusion　controlled.　When　some　molecules　existed　at　the　interface,　the　adsorption　barrier　(Ea)　appeared,　which　reduced　with　increasing　m.　This　indicated　that　those　molecules　with　long　alkyl　chain　migrated　more　easily　from　the　subsurface　into　the　surface,　which　was　attributed　to　enhanced　hydrophobic　interaction　between　the　alkyl　chains　with　increasing　m.　©　Editorial　office　of　Acta　Physico-Chimica　Sinica.