Abstract: In a microemulsoid medium containing CTMAB,n-butanol,n-heptane and water,mixed in the mass ratio of 1.0 to 0.9 to 0.1 to 9.8,and buffered at pH 9.1 with borax buffer solution,an orange colored complex (Hg∶R=1∶2) was formed by the reaction of Hg(Ⅱ) ion with dibromohydroxyphenylfluorone (DBHPF),having its absorption maximum at the wavelength of 570 nm and its apparent molar absorptivity (ε570) of 3.2×105L·mol-1·cm-1.Beer′s law was kept in the range of 6-550 μg·L-1 of Hg(Ⅱ).Detection limit (3S/N) of the method was found to be 2 μg·L-1.Based on these facts,a method for determination of traces of Hg(Ⅱ) was proposed.Tests for recovery and precision were made by analyzing 2 water samples,giving values of average recovery and average RSD′s (n=6) to be 104% and 2.7% respectively.Procedure for enrichment of traces of Hg(Ⅱ) in water sample by adsorption on sulfhydryl dextran gel (SDG) column and elution from the column by 8 mol·L-1 HCl saturated with NaCl was given in detail.