Abstract: In this study, four strains of lactic acid-producing bacteria were isolated from naturally fermented quinoa sour pulp by using plate separation technology with starch flocculation rate and lactic acid production as indicators. According to the morphological characteristics, physiological and biochemical experiments, and 16S rDNA sequence analysis, strain QSL4, QSL8, QSL9 and QSL12 were identified as Enterococcus faecium, Enterococcwus durans, Enterococcus mundtii and Enterococcus lactis, respectively. The isolated strains were applied to the extraction of quinoa protein, and its extraction characteristics in quinoa protein were analyzed by single factor experiments. The results showed that the extraction rate of quinoa protein by strain QSL12 was the highest, reaching 60.23% and 62.39% at the inoculum level of 7% and the fermentation temperature was 26 ℃, which were higher than the extraction rate results of 52.13% by alkali dissolution and acid precipitation method. This study would provide a foundation for quinoa protein extraction by acidic steeping liquor (ASL).