In order to study the physicochemical properties and evaluate the biological activity of polysaccharides from white lotus receptacle, the crude polysaccharides （WLRCP） were obtained by water extraction and alcohol precipitation method, and then purified by Sevage reagent deproteinization, combined decolorization and dialysis, and then the white lotus receptacle polysaccharide （WLRP） was obtained. The physicochemical properties were determined and analyzed by infrared spectroscopy and gas chromatography. The antioxidant capacity of WLRP in vitro was evaluated by reducing capacity, scavenging ability of DPPH and OH radicals, and its immunomodulatory activities on Macrophage RAW 264.7 of WLRP were investigated. The results showed that the content of WLRP was 84.58 g/100 g with the yield of 5.29%. Monosaccharide composition analysis revealed that WLRP was a homogeneous heteropolysaccharide including rhamnose, arabinose, xylose, mannose, glucose, and galactose in a molar ratio of 1.28∶2.10∶1.00∶2.20∶2.42∶4.76, respectively. Infrared （IR） spectroscopy analysis showed that WLRP exhibited typical absorption peaks of polysaccharides. The results of in vitro antioxidant test showed that WLRP showed a good reducing power and scavenging activities on DPPH radical and hydroxyl radical. In addition, an immunological activity assay indicated that WLRP significantly promoted the production of nitric oxide, cytokines （TNF-α, IL-6, IL-1β）, when treated with then the appropriate concentrations of WLRP. 100 μg/mL WLRP could induce the secretion of NO, TNF-α, IL-6 and IL-1β to the maximum value. Compared with the blank group, the secretion of NO, TNF-α, IL-6 and IL-1β increased by 29.89 μmol/L, 84.24 ng/mL, 33.89 ng/mL and 45.96 ng/mL, respectively. The results showed that WLRP might have potential application as an immunomodulator or supplement in functional food to enhance immunity, and this sttudy provided theoretical basis for the development of white lotus receptacle resources.