Abstract: The serious interferences caused by the co-existence of Mn,Cr,Ni,Cu,Co and Zn to the GF-AAS determination of trace amounts of cadmium in waste water were eliminated by adding 100 mg·L-1 of iron(Ⅲ) to the testing solution as matrix modifier.In the analysis of several samples of waste water,the RSD′s calculated from the analytical results fell in the range of 5.92%-7.42%,and the recoveries in the range from 94%-105%.