Abstract: Characteristics of Ganoderma lucidum polysaccharides extracted by ultrasonic wave and hot water were compared in this study.The yield of Ganoderma lucidum polysaccharides extracted by ultrasonic wave and hot water were 2.16% ±0.03% and 3.26% ±0.03%, respectively.However, the molecular weights of Ganoderma lucidum polysaccharides extracted by ultrasonic wave were smaller than those of polysaccharides prepared by hot water.AFM images showed that Ganoderma lucidum polysaccharides extracted by ultrasonic wave were looser.Moreover, antioxidant activities of two different polysaccharides were compared.The result showed that compared with the one extracted by hot water, the one extracted by ultrasonic wave was 1.3 times higher in DPPH radical scavenging activities (79.90%±0.30% at 0.5mg/mL) , 1.5 times higher in the reducing power (1.035±0.001 at 0.9mg/mL) , and 1.8 times higher in ORAC value (2275.07±115.73μmol Trolox/g) .