In this study, Lactiplantibacillus plantarum BNCC 339790 was employed to extract soluble dietary fiber (SDF) from peanut shells, followed by modification using ultrasonic, microwave, and ultra-high-pressure methods to investigate their effects on SDF properties. Ultra-high-pressure modification increased SDF's water-holding and oil-holding capacities by 1.74-fold and 2.07-fold, respectively. Characterization revealed decreased crystallinity and altered surface morphology with increased roughness and porosity after modification by the three methods. In addition, microwave-treated SDF exhibited better thermal stability. Ultrasonic treatment significantly enhanced SDF's inhibitory effects on pancreatic lipase (from 62.44 % to 83.33 %) and α-amylase (from 79.81 % to 94.94 %), demonstrated improved hypoglycemic and hypolipidemic potential. Furthermore, ultrasonically modified SDF exhibited significant anti-inflammatory activity by significantly suppressing TNF-α, IL-6, and IL-1β expression. This study provides a foundation for the further development of SDF and its promotion in functional foods and other potential applications.