Abstract: Considering the dye solution of turbidity and multicomponent,the influence of external factors such as background interference,we develop a set of dye solution absorbance detection device which is based on dual wavelength spectrophotometric and combines with ARM7 kernel processor.Without reference solution,the device solve the problem that the single wavelength couldn’t measure the multicomponent or interference dyeing liquid absorbance accurately. Experiments of three kinds of dye solutions were done respectively on the device, and the spectrum intensities of two wavelengths were measured. The absorbance curves of the dye solutions were drawn online ,where the differences between the selected two highest absorbance values were calculated. In this manner, the influence of background interference was reduced to some extent..Through experiments,we find that the device to determine the dyeing absorbance error is small and high accuracy, so it can be a mean of research for the future on-line dyeing liquid concentration measurement. *