Abstract: The complex particle system of Cu(Ⅱ)-xanthate (XT) was studied spectrophotometrically and resonance scattering spectroscopitrically. There is a maximum absorption peak at 410 nm. The A_{410 nm} is linear to the XT concentration in the range of 1.0～40×10^-5 mol/L. Its detection limit is 5.0×10^-6 mol/L xanthate. A new spectrophotometric method has been proposed for the determination of xanthate in waste water samples, with some advantages including high sensitivity, simplicity, rapidity and accuracy. The recovery is in the range of 98.0%~100%. The RSD is 0.9%~1.9%. The results of resonance scattering spectra show that there are (Cu-XT)n complex particles; in the system which exhibit resonance scattering effect at 360 nm.