Objective: To investigate the clinical characteristics and to analyze the clinical risk factors of lower extremity deep vein thrombosis (DVT) after hip fracture among elderly patients. Methods: From October 2000 to April 2010, 95 patients who suffered from hip fracture were recruited, including 30 males (mean age 75.3 +/- 12.47 years, range 60-90 years) and 65 females (mean age 77.9 +/- 11.45 years, range 61-96 years). There were 55 cases with femoral neck fracture and 40 cases with intertrochanteric fracture. Color Doppler flow imaging (CDFI) was used to screen DVT of bilateral lower extremities in all patients before orthopedic surgery and within 14 days postoperatively. All patients were treated with operation and given low-molecular-weight heparin (LMWH) for 10-14 days postoperatively to prevent DVT. Results: There were 16 patients who developed DVT preoperatively and 20 patients postoperatively. The perioperative and postoperative incidences were 16.8% (16/95) and 21.1% (20/95) respectively. 87.2% DVT were found in fractured extremities. Logistic regression analysis demonstrated a definite association of intertrochanteric fracture with postoperative DVT with odds ratio of 5.977 (P<0.05). Conclusions: There was higher perioperative DVT incidence in fractured extremities than that in the uninjured side. Intertrochanteric fracture was a risk factor for postoperative DVT. Patients with hip fracture are at a high risk of lower extremity DVT and should be screened using color Doppler ultrasound blood flow imaging (CDFI) before orthopedics surgery. Routine usage of LMWH is an effective way to prevent DVT during perioperative period. Anticoagulant and inferior vena cava filter had been proved to be effective to prevent perioperative DVT.