Abstract: Based on the principle that sulfur dioxide can inhibit the fading of MB oxidized by potassium bromate in sulfuric acid medium, a method for rapid determination of trace sulfur dioxide in beer by inhibiting fading spectrophotometry was established. 1 mol·L^-1 sulfuric acid solution, 2×10^-4mol·L^-1 MB solution, 0.1 mol·L^-1 potassium bromate solution and sample solution treated with sodium hydroxide and sulfuric acid were added sequentially to the 25 mL colorimetric tube, the mixed solution was heated in a water bath at 50℃ for 3.0 min. The absorbance of the system (A) and the blank sample system (A₀) were measured at 660 nm, to obtain the difference in absorbance (ΔA, ΔA=A-A₀). The results showed that the mass concentration of sulfur dioxide had a linearity relationship with ΔA in the range of 0.04-0.4 mg·L^-1, with detection limit (3s/k) of 0.001 mg·L^-1. The recovery test was made on the actual sample by the standard addition method, giving recoveries ranged from 96.5% to 101%, and RSDs (n=11) of determined values were found in the range of 1.8%-2.8%. The proposed method was used in the analysis of cooked beer and draft beer, and determined values obtained were compared with those obtained by national standard method of GB 5009.34-2016, with relative error in the range of -1.5%-2.0%.