Objective To investigate the risk factors for deep vein thrombosis (DVT) after bone trauma.Methods The study involved 118 patients with traumatic fractures (traumatic fracture group),21 DVT patients diagnosed by color Doppler (DVT group) and 56 healthy patients (control group).Anti-cardiolipin antibody (ACA) was determined by ELISA method.D-dimer and fibrinogen (Fib) were detected by coagulation analyzer and C-reactive protein (CRP) by rate nephelometry.Results Levels of D-dimer,Fib and CRP in traumatic fracture group were significantly increased,but were lower than those in DVT group.ACA positive rate in DVT group presented significant increase and three patients with positive ACA in traumatic fracture group all suffered from DVT.The positive rates of Fib,D-dimer and CRP in lower limb fracture group,multiple fracture group and pelvic fracture group were higher than those in upper limb fracture group (P ＜ 0.05).Levels of Fib and D-dimer showed gradual rise with growth of age,but their levels in DVT group had different degree of reduction after thrombolytic therapy.Conclusions Positive ACA and enhancement of D-dimer,Fib and CRP are risk factors for DVT after bone trauma.Levels of Fib and D-dimer in patients with bone trauma are related with age and therefore risk of posttraumatic DVT increases with age.