Abstract: OBJECTIVE To investigate the expression level of FCGR1 A mRNA and the evaluation value of the expression levels of IL-6, PCT, and hs-CRP in lung infection. METHODS Total of 113 patients with lung infection in Longyan First Hospital affiliated to Fujian Medical University between Jan 2020 and Sep 2020 were recruited as the research subjects. After pathogen culture and identification, the above-mentioned research objects were divided into the viral infection group with 60 cases and the bacterial infection group with 53 cases. Another 50 health examinations during the same period were in the control group. The serum FCGR1 A mRNA expression level, IL-6, PCT and hs-CRP levels were detected. The diagnostic value of the above factors in patients with lung infection were analyzed by ROC assay. RESULTS The differences in serum FCGR1 A mRNA, IL-6, PCT and hs-CRP among the three groups of study objects with lung infection were significant（P＜0.05）. The indexes in the bacterial infection group were significantly higher than those in the virus infection group, which were also significantly higher than those in the control group. The AUCs of combined detection for the prediction of virus infection and bacterial infection were 0.871 and 0.755. Gram-negative bacteria were detected in 25 of 53 bacterial infection patients, and 28 Gram-positive bacteria were detected. There were no significant differences in serum FCGR1 A mRNA, IL-6, PCT and hs-CRP between the two groups. CONCLUSION Serum FCGR1 A mRNA, IL-6, PCT and hs-CRP are of great value in the clinical diagnosis of patients with lung infection, and can be used to improve the treatment, which may have important guiding significance and provide a theoretical basis for the clinic.