Objective To explore the significant risk factors in patients with Tile C pelvic frac-tures.Methods We conducted a retrospective review of all patients with Tile C pelvic fractures in Nanjing First Hospital from January 2010 to December 2014.The data gathered on each patient in-cluded:age,sex,mechanism of injury,visiting time after injury,shock index,Injury severity scale (ISS),Revised trauma score (RTS),Glasgowcoma scale (GCS),lowest PaO2/FiO2 ,6 h lactate clearance rate,concomitant injures and interventious of Tile C pelvic fractures.The data were tested using Student’t-test,χ2 test and logistic regression method.Results The study include 139 consecutive patients.The total mortality was 29.5%.Among them,36 (25.9%)patients died within 48 hours after admission.Multivariate regression analysis showed that shock index (OR=2.591,95%CI 1.041-4.216), ISS (OR = 47.96,95%,CI 15.89-147.23 ),RTS (OR = 6.917,95% CI 1.147-13.862 ),GCS (OR =4.172,95%CI 2.962-6.268),lowest PaO2/FiO2 (OR= 117.016,95% CI 51.011-176.032),6 h lactate clearance rate (OR=2.785,95%CI 1.191-4.892),concurrent head (OR=6.302,95%CI 2.270-13.175)or chest (OR=12.233,95%CI 5.193-33.985)injures were associated with high morality of Tile C pelvic frac-ture (P <0.01).The performing digital subtraction angiography with intravascular embolization can cut the mortality (OR=0.887,95%CI 0.875-0.899).Conclusion In our study,high trauma score,serious shock, coma,PaO2/FiO2 decreased and 6 h lactate clearance rate decreased,combined with the head and chest inju-ry are the important reasons of mortality in patients with Tile C pelvic fracture.It’s vital to control shock actively,use trauma scale and emphasize multidisciplinary cooperation to reduce mortality in patients with Tile C pelvic fractures.