Abstract: This study aimed to screen probiotic strains suitable for high-quality fermentation of yam. Using 8 probiotic strains as test strains, the changes in acidity, viable bacteria count, total flavonoids, total polysaccharides, vitellin content, and DPPH free radical scavenging rate of mountain yam before and after fermentation were analyzed. Principal component analysis was employed for comprehensive evaluation. The results showed that all eight strains significantly increased the contents of lactic acid, acetic acid, total polysaccharides, and diosgenin in fermented yam (P<0.05). Among them, Lactiplantibacillus plantarum P9 yielded the highest total flavonoid content (0.208 g/L), which was 39% higher than that of the unfermented sample, and also the highest diosgenin content (0.290 g/L). In addition, Lactobacillus acidophilus JZ1004 and L. plantarum P9 significantly enhanced the DPPH radical scavenging ability (P<0.05). Principal component analysis indicated that L. plantarum P9 and Lacticaseibacillus casei JZ1089 performed best overall, with high scores in terms of total flavonoids, total polysaccharides, allantoin content, and antioxidant activity. Based on systematic screening considering fermentation performance, active component content, and antioxidant capacity, L. plantarum P9 and L. casei JZ1089 were identified as two excellent strains suitable for yam fermentation, providing theoretical and strain support for the development of yam-based probiotic fermented beverages.