A method for determining zinc,copper and iron in electrolysis cadmium by FAAS was established.Under experimental conditions,characteristic mass are 0.006μg/mL/1% for copper,0.015μg/mL/1% for iron,0.003μg/mL/1% for zinc ,recovery is 97.5%—98.0% for copper,99.1%—100.2%for iron,97.4%—99.1% for zinc.