Abstract: In order to develop a sugar-free quinoa fermented milk with high antioxidant capacity, single factor experiments were used to determine the fermentation ratio of the compound strain and the amount of xylitol added, and the response surface method was used to optimize the various products of the sugar-free quinoa fermented milk. The results showed that the best process for sugar-free quinoa fermented milk were: the compound starter ratio of Lactobacillus plantarum:Lactobacillus acidophilus was 2:1, the amount of xylitol added was 5%, the amount of lactic acid bacteria inoculated 3%, and the addition of quinoa pulp was 30%, the fermentation temperature was 38 ℃, and the fermentation time was 8 h. At this time, the superoxide dismutase (SOD enzyme) activity of fermented milk was the highest at 241.17 U/mL, and its physical and chemical indicators and microbiological indicators meet the requirements of national standards.