Abstract: Objective： To observe the changes of procalcitonin (PCT) after liver transplantation and investigate its diagnostic value in patients with liver transplantation, and provide reference for early diagnosis of infection. Methods： 85 cases of liver transplantation were analyzed retrospectively. According to the pathogen detection results, they were divided into infection group (n=24, pulmonary infection in 18 cases, abdominal infection in 5 cases, blood infection in 1 case) and non-infection group (n=61). PCT concentrations were compared between the two groups. The diagnostic value of PCT was analyzed by means of receiver operating. Results： PCT levels in liver transplantation patients were significantly elevated on the first postoperative day (POD 1), reached the peak on the second day (POD 2), and then decreased gradually from POD 5 to below 1 ng/mL. The levels of PCT in patients with postoperative infection were significantly higher than those in the non-infection group from POD 5 to POD 14. The PCT levels were significantly lower in the acute rejection group than in the infection group (P< 0.01). Conclusions： The level of PCT has good sensitivity and specificity in the diagnosis for infection in patients 5-14 days after liver transplantation.