Abstract: Sulfate is one of the main by-products in process to produce zinc carbonate.Accurate determination of its content is very important for the process improvements.Ultrasonic bath at 40 ℃ was used to pretreat the samples，and ion chromatography method was applied to determine the sulfate radical content.The results was quite satisfactory.The detection limit was 0.004%，and the relative standard deviation（RSD，n=12) was less than 3%.The addition standard recovery was 90% to 105%.This method gives consistent results comparing with the conventional barium sulfate gravimetric determination，but much superior in the aspects of analysis efficiency and detection limit.The method has the advantages of wide measuring range of content，simple and rapid analysis process，accurate measurement， and so on.

Key words: sulfate radical, zinc carbonate, ultrasound, ion chromatography