Abstract: Objective To investigate plasma exchange（PE）and hemodiafiltration（HDF）treatment in patients with fulminant hepatitis. Methods 119 patients with severe hepatitis were randomly divided into three groups. The basic medical treatment was the same. 47 cases in group A received PE，32 in group B received with PE+HDF. Results In group A，16 patients recovered，22 improved and 9 died，in group B，9 recovered，17 improved，and 6 died，and in group C，7 recovered，22 improved and 11 died；NO，LPS，TNF alpha dropped significantly after the treatment of liver supporting. Conclusion PE and HDF treatment in patients with fulminant hepatitis can significantly decrease TBIL，NH3，NO LPS，TNF alpha，and improve the survival rate of the patients.

Key words: Severe hepatitis, Plasma exchange, Hemodiafiltration