【Abstract】Objective To evaluate effect of artificial liver support system (ALSS) in liver failure and liver transplantation.Methods Forty-four patients with liver failure (including 12 undergoing liver transplantation) were treated with MARS or plasma exchange. The changes of toxic substances and cytokines in blood were detected before and after treatment. Results ALSS therapy achieved a remarkable improvement in clinical symptoms and physical signs. After ALSS treatment, there was a significant decrease in total bilirubin, total bile acid, alanine aminotransferase, creatinine, urea nitrogen, blood ammonia and endotoxin levels(P＜0.05); the levels of serum NO, TNF-α, IL-4 and IL-6 were significantly decreased(P＜0.05); there was no statistical change in erythrocytes, leukocytes and platelets. The survival rate of 30 liver failure patients caused by severe hepatitis B was 60.0%(18/30). Six patients with acute liver failure were successfully performed liver transplantation. Two patients in 6 with acute liver failure after liver transplantation survived. One patient in 2 with acute liver failure after pancreatoduodenectomy survived. Conclusion ALSS plays a positive role in treatment of liver failure by removing blood toxins, NO and cytokines. ALSS also plays a substitute role for liver failure patients who are waiting for liver transplantation.