Deep Venous Thrombosis (DVT) has been recognized as a serious complication after hip surgery because it can be followed by fatal Pulmonary Embolism (PE) and distant lower extremity deep venous insufficiency [1]. We conducted a controlled clinical study on the efficacy and safety of DVT prevention using low-molecular heparin in 54 patients who underwent hip surgery in our department from January 2005 to October 2006, randomly divided into a medication group and a control group. Cases aged >40 years, those without thromboembolic disease within 3 months, and without coagulation dysfunction were selected for the study. Those with history of heparin allergy, history of gastroduodenal ulcer, severe liver and kidney disorders, and severe cardiovascular and cerebrovascular diseases were excluded. There were 23 males and 31 females, aged 43-78 years, weighing 45-78.5 kg; type of surgery: 21 cases of artificial total hip replacement (THR), 25 cases of powered hip screw internal fixation (DHS), and 8 cases of acetabular fracture reconstruction plate internal fixation. In the drug group, low molecular weight heparin (LMWH)-fraxiparine was administered subcutaneously in the abdomen once at 8 hours and 24 hours after surgery at a dose of 0.4 ml, and once a day from the second day after surgery at a dose of 0.4 ml until the 10th postoperative day. day. No anticoagulation measures were taken in the control group. Patients were checked for signs of bleeding such as wound bleeding, skin petechiae, nasal bleeding, and bloody stools. The platelet count and PT and KTPP levels were measured preoperatively and at 2-day intervals starting from postoperative day 1; and color Doppler examinations were performed on postoperative days 7 and 14 to understand deep vein thrombosis. The results showed that DVT occurred in 12 out of 28 patients (42.8%) in the control group and in only 4 out of 26 patients (15.4%) in the medication group, and the statistical analysis x2 test showed that there was a significant difference between the two groups.