Byline: Hongliang Zeng, Song Miao, Baodong Zheng, Shan Lin, Yeye Jian, Shen Chen, Yi Zhang Keywords: antioxidant activities; Canarium album (Lour.) Raeusch; molecular structural characteristics; polysaccharide fractions Abstract The objective of this study was to investigate the multiple relations between the preliminary molecular structural characteristics and antioxidant activities of polysaccharides from Canarium album (Lour.) Raeusch (CPS). Three polysaccharide fractions, CPS1, CPS2, and CPS3, were isolated from CPS by column chromatography. CPS1 and CPS3 were mainly composed of neutral polysaccharides linked by [alpha]- and [beta]-glycosidic linkages while CPS2 was pectin polysaccharides mainly linked by [beta]-glycosidic linkages. According to the SEC-MALLS-RI system, the molecular weight of CPS1 was greater compared to CPS2 and CPS3, and the molecular weight and radius of CPS did not display positive correlation. The chain conformation analysis indicated CPS1 and CPS2 were typical highly branched polysaccharides while CPS3 existed as a globular shape in aqueous. Furthermore, the antioxidant activity of CPS2 was better than that of CPS3, while that of CPS1 was the weakest. The antioxidant activities of polysaccharide fractions were affected by their monosaccharide composition, glycosidic linkage, molecular weight, and chain conformation. This functional property was a result of a combination of multiple molecular structural factors. CPS2 was the major antioxidant component of CPS and it could be exploited as a valued antioxidant product. Article Note: The authors claim that none of the material in the paper has been published or is under consideration for publication elsewhere.