Abstract: Iron ore was dissolved with mixed acid of HClHNO3-HF-HClO4 and content of Cd in the sample solution was determined by atomic fluorescence spectrometry (AFS). The effects of some parameters such as solution acidity, dosage of Ni2+ (as a sensitizer), dosages of ascorbic acid and thiourea, working parameters of the AFS instrument on the determination were studied and optimized by experiments. The allowable quantities of the interference elements were also investigated. The results showed that the detection limit of the method for Cd was 0.20 g/L with dynamic linear range of 0～160 g/L. The recovery of the method for Cd was 95.9%～103.7% with precision of 4.5% RSD. The method has been applied to the rapid determination of Cd in iron ores.