Abstract: OBJECTIVE To explore the risk factors for invasive fungal infection（IFI） in the lung cancer patients and analyze the cytochrome CYP2 C19 gene polymorphism. METHODS Totally 93 primary lung cancer patients who were treated in oncology department of the First Affiliated Hospital of Zhengzhou University from Jan 2018 to Jan 2020 were recruited as the study objects and divided into the IFI group with 26 cases and the non-IFI group with 57 cases according to the status of IFI during the chemotherapy. The clinical data were collected from the two groups of hospitalized patients through review of electronic medical records, and the risk factors for IFI during the chemotherapy were analyzed. The single nucleotide polymorphisms of CY2 C19*2 and CY2 C19*3 loci were detected by means of DNA sequencing method. RESULTS The result of univariate analysis showed that the incidence of IFI in the lung cancer patients was associated with type of antibiotic, use of glucocorticoids and length of hospital stay during the chemotherapy（P＜0.05）, but it was not associated with the gender, age, tumor stage, mode of chemoradiotherapy, complication with diabetes mellitus or complication with hypertension. Multivariate logistic regression analysis indicated that use of antibiotics no less than 3 types, use of glucocorticoids and length of hospital stay no less than 21 days were the independent risk factors for IFI（P＜0.05）. The frequencies of fast metabolism-type, moderate metabolism-type and slow-metabolism genotypes of the IFI group were respectively 30.77%, 57.69% and 11.54%, the free drug concentrations of the three types of patients were respectively（1.87±0.66）mg/ml,（2.49±0.68）mg/ml and（3.33±0.78）mg/ml, and there were significant differences（P＜0.05）. CONCLUSION It is necessary for the hospital to take targeted prevention measures for the lung cancer patients according to the risk factors. The CYP2 C19 polymorphism has certain impact on the concentration of voriconazole, which can provide guidance for antifungal drug therapy.