The　surface　adsorption　and　micelle　formation　of　the　mixed　anionic　Gemini　surfactant　(C9pPHCNa)　and　cationic　conventional　surfactant　(C(10)TABr)　aqueous　solutions　have　been　investigated　by　surface　tension　method.　The　synergism　occurred　in　the　mixed　systems　and　yielded　maximum　synergism　at　the　mole　fraction　of　C9pPHCNa　in　the　bulk　(alpha(1))　equaling　to　0.33,　where　the　two　components　equal　electricity　mixing　in　solution.　The　corresponding　minimum　values　of　the　critical　micelle　concentration　(cmc(T)),　the　surface　tension　(gamma(cmc))　and　the　total　concentration　required　to　reduce　20　mN　center　dot　m(-1)　surface　tension　of　water　(c(20,T))　are　respectively　0.60　mmol　center　dot　L-1,　23.5　mN　center　dot　m(-1)　and　1.58x10(-5)　mol　center　dot　L-1.　Over　the　range　of　alpha(1)　studied,　the　molar　compositions　of　C9pPHCNa　and　C(10)TABr　both　in　the　micelle　and　on　the　surface　are　close　each　other,　which　reflects　strong　interaction　between　the　molecules.