The simultaneous multi-component quantitative determination was proposed without any chemical separation procedure. The method uses optimum wavelength gather obtained after hierarchical clustering and additive validation to reduce correlation of the component spectra. Information of 30 wavelength points after hierarchical clustering analysis was taken and, with the information of optimum wavelength gather, the absorptivity coefficient and component concentration of solutions were treated as independent variables, and a constrained optimization model was set up. The concentration awaiting test can be obtained after one optimization calculation for the mixed solution in which the concentration of every component is close to each other. But for some solutions in which component concentration is not close to each other, iterative optimization is necessary. The final results obtained are satisfying with a good accuracy and precision only after about 4 times of iterations, and the relative error can be controlled in 3.63%. So this method can be used for quantitative analysis of overlapping UV spectra.