Objective To observe the efficacy of extracorporeal liver support by using less fresh frozen plasma in the treat‐ment of acute‐on‐chronic liver failure.Methods A total of 45 patients with acute‐on‐chronic liver failure were divided into ob‐servation group[plasma perfusion(PP) with a small amount of plasma+ plasma exchange(PE)] ,control group 1(PE) ,control group 2(PP+PE)in terms of the amount of plasma used on the day of treatment. All the patients received artificial liver treatnts 62 times totally.Results The clinical symptoms were improved in the three groups after treatments.There were significant differences in the decrease of alanine transaminase (ALT) ,aspartate transaminase(AST) and direct bilirubin(DBil)rather than the decrease of total bilirubin(TBil)and blood ammonia among the groups.No significant difference was noted in the liver and kidney function among the three groups. The improvement of the coagulation function was poor in the observation group when compared with the control group 1 and control group 2 and there were significant differences.Conclusion During the short sup‐ply of the plasma ,plasma perfusion combined with small amount of plasma can be considered to be used in artificial liver treat‐ments ,which can effectively decrease the level of TBil ,relieve symptoms and decrease the occurrence of complications.