Abstract: Effects of membrane technology on the separation of crude polysaccharides from Ganoderma lucidum and its antioxidant activity had been studied. Fruiting body of Ganoderma lucidumwas leached by hot water, 100, 10 and 1 kDa ultrafiltration membrane were used to classify these crude polysaccharides recorded as GLP100, GLP10 and GLP1. Physicochemical properties and antioxidant activity of crude polysaccharides were compared. It had been demonstrated that three polysaccharides all have typical β-glucosidic bond absorption peaks by FTIR analysis. Congo red and circular dichroism analysis showed that the three crude polysaccharides were helix polysaccharides, GLP100 and GLP10 were triple helix polysaccharides. Results of SEM showed that the sizes of the three polysaccharides were different, which further verified that the different membranes could be used to grade the Ganoderma lucidum polysaccharides. All the three crude polysaccharides showed certain antioxidant capacity but some differences by reducing power, OH, 2, 2'-diazobis(3-ethylbenzothiazolin-6-sulfonic acid) diammonium salt cationic radical, 1, 1-diphenyl-2-trinitrobenzene hydrazine free radical scavenging. Among them, the reducing power of GLP100 was very close, and the scavenging ability of OH, ABTS and DPPH free radicals of GLP100 was better than that of the other two polysaccharides, The ABTS radical scavenging ability of GLP1 was better than the other two polysaccharides. Results showed that multistage membrane separation technology could effectively classify the polysaccharides of Ganoderma lucidum.