Sulfated polysaccharides from seaweed are highly active natural substances having valuable applications. In the present paper, attempts have been made to discuss the physicochemical and structural features of polysaccharides isolated from red marine alga Alsidium corallinum (ACPs) and its protective effect in hepatic impairments induced by tebuconazole (TBZ) in rats. Structural features were determined using High performance liquid chromatography, Fourier transformed infrared, and solid state 1H and 13C-Nuclear magnetic resonance analysis. ACPs are found to be hetero-sulfated-anionic polysaccharides that contained carbohydrates, sulfate groups and uronic acids. In vitro biological activities suggested the effective antioxidant and antimicrobial capacities of ACPs. For antioxidant testing in vivo, the biochemical analysis and plasma profiles displayed that oral administration of ACPs could mitigate blood lipid indicators, including total cholesterol, triglyceride, low and high density lipoprotein cholesterol, bilirubin, liver function indexes involving alanine aminotransferase and aspartate aminotransferase, showed that ACPs possessed obvious antioxidant activities. Besides, the intervention of ACPs potentially inhibited lipid peroxidation, protein oxidation, key enzymes of lipid metabolism (<0.001) and increased levels and antioxidant status (<0.05). Histomorphological observation confirmed that ACPs intervention could partially repair liver injuries caused by TBZ. The computational results showed that A. corallinum monosaccharides bound 1JIJ, 1HD2 and 1WL4 receptors with acceptable affinities, which together with deep embedding and molecular interactions support the antioxidant, antimicrobial and hypolipidemic outlined effects in the in vitro and in vivo findings. In view of their prominent antioxidant effects, ACPs stand for promising candidates in liver diseases and need be considered in pharmaceutical applications.