The　adsorption　of　mixed　solutions　containing　an　anionic　polyelectrolyte,　carboxymethylchitosan　(CMCH),　and　cationic　gemini　surfactants,　alkanediyl-bis-(dimethyldodecyl-ammonium　bromide)　(C12-s-C　12,　s=2,　6,　12),　has　been　investigated　by　surface　tension　method.　The　oppositely　charged　polyelectrolyte　and　the　surfactants　co-adsorb　at　the　surface　to　form　highly　surface-active　complexes.　Combining　the　surface　tension　data　with　the　Gibbs　equation,　it　is　referred　that　the　surface　layers　of　the　mixed　solutions　have　the　multi-level　structure,　which　includes　the　sublayers　beneath　an　outermost　layer.　The　gemini　surfactant　spacer　with　different　length　takes　different　conformations　in　the　surface　layers.　The　salt　(NaBr)　effects　on　the　adsorption　of　the　mixtures　have　also　been　studied.　The　spacer　length　of　C　12-s-C12　influences　the　responses　of　CMCH/C　12-s-C12　mixtures　to　the　salt　effects.　The　comprehensive　salt　effects　depend　on　the　competition　between　the　salt-enhancing　effect　and　the　salt-weakening　effect.　©　2014　Springer-Verlag.