Abstract: OBJECTIVE To explore the change of RNA oxidation product 8-oxidated guanosine（8-oxoGsn） in urine of severe liver disease patients complicated with nosocomial fungal infection and analyze its clinical significance. METHODS A total of 67 patients with severe liver diseases who were treated in Jinan People’s Hospital Affiliated to Shandong First Medical University were enrolled in the study and divided into the fungal infection group（n=7）, the bacterial infection group（n=24）, and the no infection group（n=36）. The serological indexes interleukin-6（ IL-6）, procalcitonin（PCT）, C-reactive protein（CRP） and white blood cell（WBC） as well as urine 8-oxoGsn were detected. RESULTS Of the 67 patients with severe liver diseases, 31 had nosocomial infection. Totally 62 strains of pathogens were isolated, 24（38.71%） of which were gram-positive bacteria, 31（50.11%） were gram-negative bacteria, and 7（11.29%） were fungi. The levels of IL-6, PCT, CRP and WBC of the bacterial infection group and the fungal infection group were significantly higher than those of the no infection group（P＜0.05）, the PCT level of the bacterial infection group was significantly higher than that of the fungal infection group（P＜0.05）. The urine 8-oxoGsn level was significantly higher in the bacterial infection group than in the fungal infection group, and which is significantly higher in the fungal infection than in the no infection group（P＜0.05）. The urine 8-oxoGsn level of the severe disease patients with fungal infection was positively correlated with the levels of IL-6, PCT, CRP and WBC（r=0.769, 0.845, 0.963, 0.756,P＜0.05）. The area under curve（AUC） of urine 8-oxoGsn was 0.978 in assessment of nosocomial infection, 0.780 in differential diagnosis of fungal or bacterial infection（P＜0.05）; the sensitivity and specificity were respectively 87.00% and 97.22%, 100.00% and 58.33%. CONCLUSION The urine 8-oxoGsn of severe liver disease patients complicated with nosocomial fungal infection is positively correlated with the levels of IL-6, PCT, CRP and WBC, which can be used for diagnosis of nosocomial infection and identification of species of pathogens.