This study discussed the factors that affected the production of SO2 by yeast metabolism from three aspects,such as wort composition,saccharification process and fermentation conditions.The research of the wort composition showed that increasing the content of methionine in wort can reduce the production of sulfur dioxide,increasing the content of threonine can promote the formation of sulfur dioxide,an increase in the content of sulfate in wort will improve the production of sulfur dioxide during fermentation.The research of the saccharification process showed that using adjunct materials can reduce the sulfur dioxide generation,adding zinc ion to wort can increase the generation of sulfur dioxide.The research of the fermentation conditions showed that high level of O2 in wort can reduce the production of sulfur dioxide;low pitching can increase the amount of sulfur dioxide produced by yeast;high wort concentration can significantly increase the production of sulfur dioxide.