The Ganoderma lucidum possesses a strong selenium-enrichment ability,and the selenium element they absorbed was usually transformed into the form of the selenium polysaccharide and selenoprotein.The G. lucidum was cultivated,and their mycelium was obtained to extract polysaccharides and soluble protein.The effects of selenium on the polysaccharides and protein content of the mycelium were studied,and then the antioxidant activity and antitumor activity of the polysaccharides and protein were further explored.The results showed that the Se-enriched G. lucidum has a relatively higher content of soluble protein (1.630 8 mg/g) with a selenium content of 36.905 7 μg/g as the selenium content of the fermentation broth was 95 μg/mL.Besides,the content of polysaccharides (32.070 9 mg/g) extracted in the alkaline water system assisted with the ultrasonic method was quite higher,with a selenium content of 33.864 μg/g.Compared with the control group,the polysaccharide and protein derived from the Se-enriched G. lucidum were much more potent,and we found the activity of those compounds was dependent on their concentration.Furthermore,the selenium polysaccharide showed excellent effects in inhibiting tumor cell proliferation,and its IC₅₀ value on the HCCLM,A549,and HSC-3 cells was 3.765, 3.23 and 2.267 mg/mL,respectively.However,the antitumor activity of the selenium protein was relatively weak,with its IC₅₀ value towards those tumor cells being 636.987,506.97 and 555.598 μg/mL,respectively.