Objective To study the efficacy as well as the mechanism of artificial liver support system（ALSS）in the treatment of hepatitis gravis. Methods Seventy-one patients suffering from hepatitis gravis were treated with artificial liver support system on the basis of conventional therapy．The liver function，prothrombin activity（PTA）， serum tumor necrosis factor alpha（TNF-α），endotoxin，nitrogen monoxide（NO）and clinical symptoms were observed．And the efficacy of ALSS treatment on the different stages and different types of hepatitis gravis were investigated．Results After treating with artificial liver support system ，the clinical symptoms of the hepatitis gravis patients were ameliorated．The levels of serum albumin and PTA increased obviously (P<0.05～0.01)． The levels of plasma PT, total bilirubin，serum ammonia，TNF-α，endotoxine and NO decreased significantly ( P<0.05～0.001). The response rates of acute and chronic hepatitis gravis were 61.5％ and 25.6％ respectively，and the response rates of chronic hepatitis gravis in early stage，middle stage and late stage were 72%、42%、0% respectively. Conclusions The ALSS is effective in treating hepatitis gravis.It is more suitable to use ALSS in early and middle stage of chronic hepatitis gravis．And ALSS may significantly decrease the levels of pathologic components such as TNF-α、endotoxin and nitrogen monoxide．As a result，ALSS can also alleviate the injury from immunoreaction and increase the survival rate．The clinical symptoms and biochemistry indexes can be used to judge the prognosis of hepatitis gravis after ALSS treatment.