Abstract: OBJECTIVE To study the structural characteristics and biological activities of the polysaccharides from insect Blaps rynchopetera Fairmaire. METHODS The crude polysaccharide components(BP50, BP75 and BP90) of Blaps rynchopetera Fairmaire were extracted by method of water extraction and alcohol fractional precipitation. BP90 was further isolated and purified by Sephadex G-75 to obtain polysaccharide component(BP90-Ⅱ). Structural characteristics of polysaccharide from Blaps rynchopetera Fairmaire were investigated by using phenol-sulfuric acid method, BCA method, HPLC, gel permeation chromatography coupled with multi-angle laser light scattering detector and reflective index detector, infrared spectrum, respectively. Antioxidant activities of different polysaccharide components were evaluated by scavenging capacity on DPPH, ABTS, and OH free radicals. Additionally, anti-inflammatory effect of polysaccharide from Blaps rynchopetera Fairmaire was tested on lipopolysaccharide-stimulated BV-2 microglia. RESULTS The antioxidant activity showed that BP90 had the strongest antioxidant capacity. The content of total sugar and protein in BP90-Ⅱ was 82.13% and 11.28%, respectively. The infrared spectra of BP90-Ⅱ showed typical absorption peaks of polysaccharide. With a weight-average molecular weight of 56 200 g·mol^-1. The BP90-Ⅱ was composed of mannose, rhamnose, glucosamine, glucuronic acid, galacturonic acid, galactosamine, glucose, galactose, arabinose and fucose, among which the content of glucose was the highest, up to 74.85%. The results showed that BP90-Ⅱ had inhibitory effect on NO production. NO inhibition rate of BP90-Ⅱ at the concentration of 10 μg·mL^-1 and 100 μg·mL^-1 was (14.86±1.63)%, (36.43±5.62)%, respectively. CONCLUSION The polysaccharide from Blaps rynchopetera Fairmaire have significant anti-oxidation ability and certain anti-inflammatory activity. The medicinal and edible value of polysaccharide from Blaps rynchopetera Fairmaire should be developed.