Abstract： Objective　To investigate the causes for mental state abnormality in post liver transplantation patients during ICU. Methods　The clinical and laboratory data of 35 patients following liver transplantation during ICU were collected. By using Sedation-Agitation-Scale the patients were divided into agitation group and control group, and the data in the two groups were compared. Results　There was no significant difference between the agitation group and the control group in age, sex, postoperative liver and renal function and the blood concentration of cyclosporin A. In the agitation group the duration of intravenous cyclosporin A was significantly longer (P<0.05), the number of catheter in vivo (P<0.01), the case proportion needing critical monitoring blood glucose concentration (P<0.05), the case proportion using tienam+ganciclovir+fluconazole (P＜0.05) and the time staying in the ICU (P＜0.05) was significantly increased as compare with those in the control group. Mean heart rate, respiratory rate and artery pressure in the agitation group were higher than in the control group. Conclusions　Mental state abnormality in the patients following liver transplantation during ICU was contributed to the comprehensive causes.