Objectives To evaluate the therapeutic effect of continuous hemodiafiltraton(CHDF) therapy on liver support and complications management in patients with chronic severe hepatitis B. Methods Seventy-eight end stage chronic severe hepatitis B patients complicated with MODS or MOF were randomly divided into CHDF therapy group (42 patients) and control group (36 patients), 116 CHDF treatments were performed with average of 3.2 sessions per patient, all were evaluated with liver function, hemogram, ammonia level, blood coagulation, kidney function, electrolyte and acid/base balance before and after the treatment period. Results CHDF treatments result in safely effective improvement of multiple organ function and various complications including liver, renal, cerebral, SIRS, hemodynamics and clinical severe manifestations such as edema and tympanites, and marked decrease of serum ammonia level, HE grade or hydrocephalus, which contribute to the improvement in immediate survival rate. Conclusions CHDF technique represents a therapeutic liver support therapy, and can be regarded as a valid treatment option on clinical managements in severe hepatitis patients complicated with MODS or MOF. 