Abstract: In a borate buffer medium of pH 9.80, and in the presence of CTMAB, ternary micellar complexes were formed by the color reagent xylenol orange (XO) with Cu(Ⅱ), Cd(Ⅱ), Ni(Ⅱ) and Zn(Ⅱ) separately, and based on these sensitive color reactions, these 4 elements could be determined only individually, because of the interference of serious overlapping of their absorption spectra. By applying the algorithm of artificial neural network based on back propagation, the problem of spectral overlapping was overcomed and the 4 above mentioned elements were determined simultaneously in the presence of each other, giving relative deviations (%) between the experimental values and the predicted values≤0.1%.