Abstract: In a TEA-HCl buffer medium of pH 7.8,and in the presence of Triton X-100,a stable violet colored ternary complex was formed among U(Ⅵ),QAMDHB and F--ion in the mole ratio of 1∶1∶1.The absorption maxima of the complex was found at the wavelength of 562 nm,where the molar absorptivity of the color system was found to be 8.0×104L·mol-1·cm-1.Beer′s law was kept in the concentration range of 0-20 μg of U(Ⅵ) per 10 mL of solution.The method has been applied to the analysis of environmental water sample after an enrichment of the uranium by solid-phase extraction through a TBP elution resin solid-phase extraction column (7 mm×30 mm,30 μm).The acidity of the sample solution for solid-phase extraction was chosen as 5 mol·L-1 HNO3,water was used as eluant and the elution was carried out in the reverse direction.The RSD′s obtained were in the range from 1.8%-2.4%,and the recoveries were in the range of 97%-104%.