This is the first report of the sensitizing effect of cation surfactant on the enhanced resonance light scattering (RLS) resulted from the interaction of organic dyes with Deoxyribonucleic acid (DNA). On the conditions of pH 10.4 ～11.8 and ionic strength being less than 0.050, the interaction of brilliant green (BG) with DNA results in enhanced RLS signals at 398.0 and 467.2 nm overloaded some shoulder peaks in the enhanced region. It was found that the interaction was sensitized by the presence of cetyltrimethylammonium bromide (CTMAB). If 2.0～3.2×10-5 mol/L CMAB was used in the interacting medium, DNA in the range of 0～1.2 (mg/L could be detected with the limit of detection being less than 5 μg/L. Four synthetic samples were analyed with reproducibility