We studied the effects of Catharsius molossus (a Chinese medicinal insect) on the cell growth, fermentation kinetics of key bioactive substances and anti-cancer activity of Ganoderma lucidum in submerged fermentation. The results showed that C. molossus at all the tested concentrations had no stimulatory effect on the cell growth. However, addition of C. molossus at 5 g/L lead to significant effects on the fermentation kinetics of polysaccharides and triterpenoids of G. lucidum, and at 7th day in fermentation process, the yields of polysaccharides and triterpenoids reached 2.81 g/L and 539.0 mg/L, respectively, while they were 2.25 g/L and 428.2 mg/L in control. In vivo anti-cancer studies showed that the inhibitory rates of control fermented G. lucidum (CFG) and a combination of water extract from C. molossus and CFG on the developed tumor (Heps) in mice were 41.61% and 42.24%, respectively. Moreover, the inhibitory rate of the G. lucidum fermented with C. molossus (GFC) reached 57.21%, which was enhanced 37.49%, compared to the inhibitory rate of the control fermented G. lucidum. These results suggest that supplementation of C. molossus in submerged fermentation of G. lucidum lead to a significant enhancement of the anti-cancer activity of cultured G. lucidum.