Abstract: As one of the most common industrial waste gases, the emission of SO₂ may pose a serious threat to the environment and to organisms, and people pay more and more attention to the efficient and portable gas detectors. Compared with traditional detection routes, electrochemical and semiconductor SO₂ gas sensors have been rapidly developed in recent years for their simple structure, easy-operation, excellent performance, and low-cost. The research status at home and abroad of the electrochemical and semiconductor SO₂ gas sensors is presented; the research of device structures, sensitive materials, sensing mechanisms and major technical difficulties in practical application are reviewed, and discuss their development trend in the future.