Abstract: In this study, Baoding Qishan yam was used as the raw material, and Lactiplantibacillus plantarum was inoculated for fermentation. With the viable count in yam powder and sensory evaluation score as indicators, the optimal fermentation parameters for fermented yam were investigated via single-factor experiments and response surface optimization experiments on fermentation process parameters. Subsequently, fermented yam was powdered by freeze-drying, spray-drying, microwave drying, and hot-air drying. The quality of probiotic yam powder prepared by the four drying methods was evaluated based on moisture content, bulk density, polysaccharide content, total polyphenol content, total flavonoid content, viable count, and starch digestibility, so as to select the most suitable method for drying and powdering of fermented yam. The results showed that the optimal preparation process for fermented yam was determined as follows: Inoculum size of 2%, fermentation time of 48 h, and fermentation temperature of 37 ℃. Under these conditions, the highest viable count and the highest sensory evaluation score in fermented yam were achieved, which were 9.07 lg (CFU/mL) and 91.36 points, respectively. Probiotic fermentation could significantly increase the contents of polysaccharides, total polyphenols, total flavonoids, and resistant starch (RS) in yam powder (P<0.05), while significantly (P<0.05) reduced the content of rapidly digestible starch (RDS). The quality of yam powder prepared by freeze-drying was the best, followed by that prepared by spray-drying. Although yam powder prepared by microwave drying had the highest total polyphenol and total flavonoid contents, it severely reduced the polysaccharide content in yam. Microwave drying and hot-air drying, while drying the samples, killed a large number of probiotics in yam powder, thus reducing the quality of the final product. These results suggested that probiotic-fermented yam could significantly improve the quality of yam, and among the four drying methods, freeze-drying and spray-drying were more suitable for the preparation of probiotic yam powder compared with microwave drying and hot-air drying.