Two water-soluble polysaccharides (ACPS1 and ACPS2) were isolated from the roots of Actinidia Chinensis by DEAE-52 cellulose and Sephacryl S300 chromatography. Preliminary structural characterization was conducted by physicochemical property, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analysis. ACPS1, with an average molecular weight of 5.58 × 10(5) Da, was mainly composed of rhamnose, arabinose, xylose, mannose and galactose in an approximate molar ratio of 1.48:4.28:4.30:1.00:17.83. ACPS2, with a high average molecular weight of 1.23 × 10(6) Da, mainly contained rhamnose, arabinose and galactose in a molar ratio of approximately 1.00:2.33:6.61. Both ACPS1 and ACPS2 exhibited the remarkable antioxidant activity to scavenge the DPPH radical and significant protective effects on H2O2-induced HEK 293 cells death in a concentration-dependent manner. Meanwhile, in vitro immunomodulatory activities of the two polysaccharides were evaluated. The results showed that treatment with 50-300 μg/mL of the samples could increase NO production and phagocytic activity of macrophages in a dose-dependent manner. The present results suggested that the two polysaccharides from Actinidia Chinensis may be potential antioxidant and immunomodulatory agents for preparing functional foods and nutraceuticals applied in food and pharmaceutical industries.