Objective：To investigate the clinical effect of plasma exchange （PE） plus continuous hemodiafiltration （CHDF） on pre-liver failure. Methods：Retrospective analysis was made on the clinical data in the 49 patients with pre-liver failure. Twenty-nine pa－tients were treated by PE combined with CHDF based on medical supporting treatment and 20 patients were treated by medical sup－porting treatment alone. Their therapenutic effects on biochemical parameters and clinical outcome were observed and compared be－tween the two groups. Results：Symptoms such as fatigue，poor appetite，and jaundice were relieved after non-biologic artificial liver support system（NBALSS）. The levels of C reactive protein（CRP），interleukin（IL）-6，alanine aminotransferase（ALT），total bilirubin （TBIL） after treatment decreased，and serum prothrombin activity（PTA） level increased in the PE plus CHDF group. While，all of the biochemical indictors after treatment differed significantly between the two group（all P<0.05）. Patients in the treatment group had a significantly higher improvement rate（ χ2=5.935，P=0.015） compared with that in the control group. Conclusion：The curative effect of PE plus CHDF based on medical supporting treatment is more remarkable than that of medical supporting treatment alone；therapeutic PE plus CHDF significantly increases the improvement rate of patients with pre-liver failure.