Abstract: In order to explore the antioxidant activity of cinnamon polysaccharides, the protein was removed from the water extract of cinnamon(CE)to obtain crude polysaccharides. By using cellulose ion column DE-52 and propylene dextran gel S-300, the cinnamon neutral polysaccharides(CNP) was obtained. The relative molecular mass(M_r) of CNP was determined by gel permeation chromatography(GPC), and the monosaccharide component of CNP were determined by pre-column derivatization high performance liquid chromatography. The connection modes of its monosaccharides were determined by methylation method and nuclear magnetic resonance method. The in vitro chemical model was used to study the scavenging effects of CNP on DPPH· and ABTS⁺·. The results indicated that the weight average relative molecular mass(M_w) of CNP was 3 630 and the main monosaccharide was glucose. Three kinds of connection modes of monosaccharides were 1, 4, 5-Ac₃-2, 3, 6-Me₃-Glu, 1, 5-Ac₂-2, 3, 4, 6-Me₄-Glu, and 1, 5, 6-Ac₃-2, 3, 4-Me₃-Glu. The determination results of free radicals scavenging by CNP showed that when the mass concentration of CNP was 2 g/L, the DPPH· scavenging rate reached the maximum of 84%, the ABTS⁺· scavenging rate reached 60%. Although the free radical scavenging rate of CNP was lower than that of Vc, the DPPH· scavenging effect was comparable to that of Vc when the concentration of CNP reached 0.5 g/L. Therefore, the antioxidant activity of cinnamon neutral polysaccharide was good and had good development value.