Abstract: OBJECTIVE To investigate the diagnostic effect of procalcitonin（PCT） and prealbumin（PA） on postoperative pulmonary infection in patients with lung cancer.METHODS Patients treated with lung cancer radical resection from Aug. 2015 to Jun. 2018 in the hospital were selected as the research objects. 40 cases of patients with pulmonary infection after surgery were randomly selected as the infection group, 40 cases of patients without pulmonary infection after surgery in the same period were included as the uninfected group, and 40 cases of healthy people with medical examination were taken as the control group. The levels of serum PCT and PA in the patients undergoing lung cancer radical resection on the 1 st day, 3 rd day and 5 th day after the surgery and the healthy people in the control group on the day of medical examination were observed, and the sensitivity of the diagnosis of postoperative pulmonary infection by the two kinds of indexes was analyzed.RESULTS From the 1 st day to the 5 th day after surgery, the PCT levels in the infected group showed a significant increase, which were respectively（1.51±0.46）ng/ml,（3.48±1.15）ng/ml and（6.82±3.49）ng/ml. There were significant differences in the PCT levels at different time points between the infected group and the uninfected group（P＜0.05）. The PA levels of the two groups on the 3 rd day after surgery were low, the infected group was（123.67±32.15）ng/ml and the uninfected group was（142.72±33.02）ng/ml, and there was a significant difference between the two groups（P＜0.05）. The positive rates of PCT and PA in the infected group were respectively 65.00% and 22.50%, which were higher than those in the uninfected group, but there was no significant difference in the positive rates of PA between the two groups. The sensitivity, specificity and area under the curve of PCT in the diagnosis of pulmonary infection after lung cancer surgery were 65.00%, 77.50% and 0.809 respectively. The sensitivity and specificity of PA in the diagnosis of pulmonary infection after lung cancer surgery were 47.50%, 22.50%, and the area under the curve was 0.382.CONCLUSION The PCT level of patients with pulmonary infection after lung cancer surgery increases continuously, which is of certain value in the clinical diagnosis of pulmonary infection. Although the PA level of patients with lung infection is lower than that of patients without lung infection, its sensitivity and specificity in the diagnosis of pulmonary infection in patients after lung cancer surgery are poor, so it does not have diagnostic value.