Abstract: Objective To evaluate the value of plasma exchange (PE) therapy for chronic severe hepatitis B (CSHB) by analyzing the influence factor of treatment of CSHB with PE and internal comprehensive therapy.Methods To observe the influence to efficacy and biochemical index with treatment of CSHB with PE and internal comprehensive therapy, at the same time, to observe the influence to efficacy with different plasma quantity、exchange time、phase of the course of disease by comparing with 422 cases of CSHB from 1997 to 2004.Results The efficacy of PE is not related to age、sex、blood type;it is related to hepatic encephalopathy and hepatorenal syndrome;it is not related to peritonitis and portal hypertention, The efficacy of PE is passively related to complications and positive to times of exchange.It is not certain that the therapy for CSHB with PE is better than internal comprehensive treatment.PE can remedy partly the hepatic function and blood routine index of patients in different course of disease, and improve the efficacy of clinical comprehensive treatment.Conclusion It helps to improve the efficacy of PE through choosing appropriate quantity of exchange、exchange times and auxiliary treatment opportunity.