Exopolysaccharides (EPS) are important metabolites produced by lactic acid bacteria (LAB), exhibiting diverse biological activities. However, their application is limited by low production levels. This study aimed to isolate, characterize, and evaluate the bioactivities of an EPS (EPS-PAD) from high-yield LAB in kefir grains. A novel EPS-PAD was isolated, purified and analyzed using molecular weight determination, monosaccharide composition analysis, nuclear magnetic resonance (NMR), and methylation analysis. Moreover, the antioxidant activity and anti-inflammatory activity of EPS-PAD were investigated as well. The results showed that EPS-PAD had a relatively low molecular weight (42.7 kDa) and consisted of arabinose, glucose, and galactose (molar ratio 1:1:3). Furthermore, structural analysis indicated it possessed an α-pyranose configuration with branched chain residues. Remarkably, EPS-PAD exhibited potent radical scavenging activities, with rates of 62 % (1,1-diphenyl-2-picrylhydrazyl radicals), 64 % (2,2′-azinobis (3-ethlybenzothiazoline)-6-sulfonic acid radicals), and 76 % (hydroxyl radical). In addition, at 400 μg/mL, EPS-PAD significantly suppressed the production and mRNA expression of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) and upregulated the production of anti-inflammatory cytokine IL-10 in RAW264.7 cells. These findings provide a scientific basis for EPS-PAD from kefir grain LAB as a promising natural antioxidant and anti-inflammatory agent with significant application potential.