Abstract: The thallium in lead smelting slag has high toxicity. Since the occurrence matrix is complex, there is no standard method for the analysis of thallium in lead smelting slag. In this study, a method for the determination of thallium by inductively coupled plasma atomic emission spectrometry(ICP-AES) after adsorption preconcentration with polyurethane foam was established. The sample was digested with mixed acid system containing 15 mL of hydrochloric acid, 5 mL of nitric acid, 10 mL of hydrofluoric acid, 2 mL of perchloric acid, 5 drops of sulfuric acid(1+1) and bromine water. The interference of silicon and carbon could be effective eliminated. Meanwhile, thallium was converted to Tl(Ⅲ) which could be adsorbed. The optimization experiments indicated that the adsorbing effect of Tl(Ⅲ) by polyurethane foam was best when 0.10-0.20 g(4-6 drops) of bromine water was added into 5% aqua regia medium to make the solution show stable pale yellow. After adsorption, 10.00 mL of 3.0 g/L sulfurous acid solution was used as the eluent to achieve the quantitative elution of thallium by heating in boiling water for 20 min. Tl 190.856 nm was selected as the analytical line. The emission spectral intensity of thallium showed good linear relationship with the mass concentration in range of 0.50-20.00 μg/mL, and the linear correlation coefficient was 0.999 8. The limit of detection of this method was 1.12 μg/g. The content of thallium in actual lead smelting slag sample was determined according to the experimental method. The relative standard deviation(RSD, n=9) of determination results were between 3.1% and 4.0%, and the spiked recoveries were between 95.5% and 101.7%. The measurement results were consistent with those obtained by inductively coupled plasma mass spectrometry(ICP-MS). The proposed method was accurate and reliable, which was suitable for the quantitative analysis of thallium in lead smelting slag.