Objective To investigate the effect of plasma exchange (PE) in the treatment of chronic severe hepatitis. Methods 70 cases with chronic severe hepatitis were divided randomly into two groups:treatment group and control group. The treatment group combined with PE based on combined therapy of internal medicine, control group was only performed combined therapy of internal medicine. The therapeutic efficient rate was analyzed by con-trast after one month. Results The level of TBil,ALT,CHO,CHE,PTA,BUN and Cr of patients in treatment group improved more obviously than those in control group(P <0.05). The total effective rate was 62.86% in treatment group and was 31.43% in control group,and there were significant differences in two groups(P <0.05). The death rate was 11.42% in treatment group and was 31.42% in control group,there were significant differences in two groups (P < 0.05). Conclusion PE combined with therapy of internal medicine can obviously improve therapeutic efficient rate of chronic severe hepatitis,which is an safe and effective method.