Abstract: Objective：To study the therapeutic effects of artificial liver support system(ALSS) of plasma exchange(PE) combined with continuous hemodiafiltration(CHDF) on severe chronic hepatitis B. Methods：87 chronic severe hepatitis B patients(group A) were treated by PE combined with CHDF based on medical supporting treatment.Their therapeutic effects on clinical symptoms and biochemical indicators were observed and compared with 94 severe chronic hepatitis B patients(group B), who were treated only by PE without CHDF. Results：The recent improvement rate of clinical symptoms, hypokalemia , hyponatremia and consciousness rate of hepatic encephalopathy in group A were 100%(87/87), 80%(33/41), 93%(27/29) and 55%(12/22) respectively, while 48%(45/94), 7%(3/42), 7%(2/30) and 20%(5/25) respectively in group B. There were significant differences between two groups (P<0.05). The effective power and survival rate in the near future in group A (80% and 48%) were much higher than in group B (47% and 31%) (P<0.05). The most common adverse reaction was plasma allergic reaction. Severe adverse reaction such as hypotension and pulmonary edema were not found. Conclusions: Based on medical supporting treatment, PE combined with CHDF can increase the recent survival rate and the consciousness rate of hepatic encephalopathy, nomalize electrolyte disturbance. It can be one of the major treatments for severe chronic hepatitis B patients.