The　color　reactions　of　4,　5-dibromophenylfluorene　(diBr-PF)　with　twelve　metal　ions　in　the　presence　of　surfactants　have　been　reported.　It　has　been　shown　that　the　molar　absorptivities　(epsilon)　of　most　of　these　complexes　are　10(5)　order,　even　epsilon　=　10(6)　(i.e.　Fe(III),　Be(II),　Sn(IV)　ions).　The　diBr-PF　is　a　highly　sensitive　chromogenic　reagent.　pi-electron　distribution　of　the　diBr-PF　has　been　calculated　primarily　by　means　of　the　Huckel　molecular　orbital　(HMO)　method.　The　equilibrium　shape　of　the　diBr-PF　has　been　shown.　The　acidic　dissociation　constants　and　distributing　curves　of　the　diBr-PF　are　determined　and　constructed　respectively.　The　mechanism　of　synergistic　effect　of　mixed　cationic-nonionic　surfactants　on　the　Me-diBr-PF　color　reactions　has　primarily　been　studied.　It　is　deduced　that　the　microenvironment　of　mixed　micelles　of　mixed　surfactants　is　different　from　that　of　the　one　surfactant,　and　the　changes　of　a　series　of　analytical　characters　primarily　result　from　the　formation　of　mixed　micelles.