A new dual-wavelength visible absorption spectroscopy method (DWO-VIS) for quantifying copper in food was established. In tris-hydrochloric acid buffer medium of pH 6.86, ponceau S reacted with copper(Ⅱ) to form an ion association complex with obvious a positive absorption peak and a negative absorption peak in visible area. The maximum positive absorption wavelength and the maximum negative absorption wavelength were located at 445 nm and 510 nm respectively. copper(Ⅱ) obeys Lombard Beer’s law in definite mass concentration range of 0.06 - 1.6 mg/L（positive absorption，445 nm） and 0.04 - 1.6 mg/L（negative absorption，510 nm）and 0.03 - 1.6 mg/L（DWO-VIS ，445 nm + 510 nm） respectively. Their apparent molar absorptivity (κ) were 8.70×103（positive absorption method） and 2.04×104(negative absorption method) and 2.92×104（DWO-VIS method）L/(mol·cm) respectively with the limit of quantitation were 0.62,0.38 and 0.26 mg/100 grespectively. The absorption spectral characteristic and optimum reaction conditions and effect of the coexistence material were studied. The dual-wavelength visible absorption spectroscopy method was applied to determine the content of copper in biscuits and noodles and milk powder with spiked recoveries and relative standard deviation (RSD) (n=5) found were in the ranges of 97.9% - 102% and 2.5% - 2.8% respectively.