OBJECTIVE：To observe therapeutic efficacy and safety of low molecular heparin calcium（fraxiparine）combined with vapour-pressure type blood circulation driver for the prevention and treatment of postoperative lower limb deep vein thrombosis（ DVT）in elderly fracture patients. METHODS：80 elderly patients receiving fracture surgery were randomly divided into control group and observation group，with 40 cases in each group. Control group only received preventive measures for lower limb DVT under the action of vapour-pressure type blood circulation driver，while observation group was additionally given Low molecular heparin calcium injection on the basis of control group，Preoperative 2 h，postoperative 12 h and 24 h，0.4 ml was administrated； Postoperative d2-d3，0.4 ml was subcutaneously injected；postoperative d4，0.6 ml was administrated and lasted for 10 d. The incidence of lower limb venous thrombosis，therapeutic efficacy，the changes of blood rheology indexes and the cross-section diameter difference of uninjured side limb were observed in 2 groups；the incidence of ADR was compared between 2 groups. RESULTS： The observation group；total effective rate（95.00％）was higher than control group（72.50％），with statistical significance（ P＜0.05）. After treatment，the cross-section diameter difference of side and uninjured side limb in observation group decreased to（1.10±0.87）cm，which was significantly lower than control group（2.59±1.55）cm，with statistical significance（P＜ 0.05）. The blood viscosity at both high and low shear rates，plasma viscosity and fibrinogen of observation group were all better than those of control group，with statistical significance（P＜0.05）. No obvious ADR was found in 2 groups. CONCLUSIONS：In the prevention of lower limb DVT in elderly fracture patients，Low molecular heparin calcium injection combined with vapour-pressure type blood circulation driver show high effective rate，significantly improve blood rheological index and lower the incidence of lower limb DVT with good safety.