Abstract: In a 0.06 mol·L-1 H2SO4 medium,a complex was formed between Sb(Ⅲ) and pyrogallic acid,giving a sensitive derivative polarographic wave with its peak potential at -0.4 V(vs.SCE).The sensitivity of this polarographic reaction was remarakably increased in the presence of microamounts of selenium(Ⅳ). Linear relationship between peak current and Sb concentration was ranged in 0.03-1.2 mg·L-1.Detetion limit of the method was found to be 0.004 mg·L-1.The proposed method has been applied to the determination of trace antimony in zinc electrolyte giving RSD′s in the range of 1.8%-2.2% and recoveries in the range of 95.0%-105.0%.