Abstract: OBJECTIVE To explore the guiding effect of CYP2 C19 gene polymorphism on drug therapy of the patients with invasive fungal infection. METHODS A total of 103 patients with invasive fungal infection who were treated in hospitals from Jan 2017 to Jun 2018 were recruited as the study objects and divided into the high metabolite（EM） group, the moderate metabolism（IM） group and the low metabotropic（PM） group according to the result of DNA gene test.The clinical data were collected from the three groups of patients and were compared, the frequency of CYP2 C19 genotype was taken for statistics, and the treatment parameters were analyzed after the patients were grouped according to the type of metabolism. RESULTS There were significant differences in BMI, diabetes mellitus, long-term smoking history, NEU and TBil among the three groups of patients.There were 25 cases of 681 GG-636 GG genotype in the EM group; there were 47 cases of double-digit genes in the IM group, including 30 cases of 681 GA-636 GG genotype and 17 cases of 681 GG-636 GA genotype; there were 31 cases of double-digit genes in the PM group, including 18 cases of 681 AA-636 GG genotype and 13 cases of 681 GA-636 GA genotype.The length of ICU stay of the IM group was（45.76±5.49） days, significantly longer than that of the EM group and the PM group, and the cost of antibacterial treatment of the IM group was（5867.90±342.16） yuan, remarkably more than that of the EM group and the PM group（P＜0.05）.The incidence of complications of the PM group was 16.13%, significantly higher than that of the EM group and the IM group（P＜0.05）. CONCLUSION The patients with double-digit genotype are dominant among the patients with invasive fungal infection, it is necessary to combine with the CYP2 C19 gene polymorphism so as to guide the drug therapy, and there are significant differences in the length of ICU stay, cost of antibacterial treatment and incidence of complications.