Ultraviolet-visible absorption spectral properties of Sudan III in different solvents were studied. The results show that the main absorption peaks are located in 200-230 nm, 340-360 nm and 490-510 nm. When Sudan III is in polar solvent, two absorption peaks appear in the mid-ultraviolet region, 200-230 nm. And when it is in nonpolar solvent, the absorption changes from two peaks to one peak with the concentration of Sudan III increasing. When it is in composite solvent, the two absorption peaks disappear, but one absorption peak appears at 310 nm. Molar absorptivities of Sudan III in the five solvents were determined, whose order of magnitude was 10(4).