Objective To explore the effectiveness of Colorado 2TM system in the stabil ity reconstruction of sacroil iac joint fracture and dislocation in Tile C pelvic fracture. Methods Between February 2009 and January 2011,8 cases of Tile C pelvic fracture were treated with Colorado 2TM system. There were 3 males and 5 females with an average age of 34.4years (range,22-52 years). Fractures were caused by traffic accident in 3 cases, by fall ing from height in 3 cases,and by crash of heavy object in 2 cases. According to Tile classification, 5 cases were classified as C1-2, 2 cases as C1-3,and 1 case as C2. The time between injury and operation was 5-10 days (mean, 7 days). After skeletal traction reduction, Colorado 2TM system was used to fix sacroil iac joint, and reconstruction plate or external fixation was selectively adopted. Results The postoperative X-ray films showed that the reduction of vertical and rotatory dislocation was satisfactory, posterior pelvic ring achieved effective stabil ity. All the incisions healed by first intention, and no blood vessel or nerve injury occurred. Eight patients were followed up 6-24 months (mean, 12 months). No loosening or breakage of internal fixation was observed and no re-dislocation of sacroil iac joint occurred. The bone heal ing time was 6-12 months (mean, 9 months). According to Majeed’s functional criterion, the results were excellent in 5 cases, good in 2 cases, and fair in 1 case at last follow-up. Conclusion Colorado 2TM system could provide immediate stabil ity of pelvic posterior ring and good maintenance of reduction effect, which is an effective method in the therapy of sacroil iac joint fracture and dislocation in Tile C pelvic fracture.