Abstract: The effect of surfactants on a series of Me-5-Br-DEPAPand Me-5-Cl-PADABcolor systems have been investigated in detail. The results indicated that the sensitizing effect of surfactants on the color systems and strengthening or weakening of the sensitizing effect are concerned with the valence of the metal ion, the type of its complex and structure of color reagents besides the characters of surfactants. The mechanism of the effect of surfactants on the color systems was discussed preliminarily.