Among thrombotic diseases, lower extremity deep vein thrombosis is one of the more prevalent and dangerous ones. Sedentary and lack of limb activity can lead to slow blood flow, which is an important factor for thrombosis. In addition, lower extremity DVT is more common in patients after major surgery, especially in postoperative patients of orthopedics and gynecology. The early symptom of lower limb deep vein thrombosis is swelling and pain in lower limbs, especially the sudden unilateral lower limb swelling and pain, local feeling of heaviness or pain, and the pain increases when standing and walking, patients should be highly alert to lower limb deep vein thrombosis, then they should visit vascular surgery to exclude the possibility of thrombosis. The following measures should be kept in mind for the prevention of postoperative lower limb deep vein thrombosis: 1. For patients at high risk of lower limb deep vein thrombosis, such as obesity, history of lower limb trauma, advanced age, long-term bed-ridden and combined hypertension and diabetes, a targeted plan should be formulated on the basis of preoperative assessment, and blood-activating or anticoagulant drugs should be given early if necessary, and monitoring of coagulation function should be strengthened. 2.Strengthen postoperative care. If patients need to be bedridden, they should be turned regularly in the early stage and encouraged to carry out bed activities, such as deep breathing, effective coughing, frequent active activities of feet and toes and flexion and extension of lower limbs, in order to reduce venous blood stasis. High-risk patients should elevate the lower limbs 20-30 degrees to promote blood reflux, and wear medical elastic stockings for the lower limbs if necessary. 3.If there is no special situation, postoperative patients should get out of bed as early as possible, generally in 2-3 days after surgery, they can sit up at the bedside and move their limbs, and then gradually increase the amount of activity. 4.Strengthen dietary care, it is advisable to eat light, low salt, low fat, vitamin-rich, high protein and high fiber food to prevent constipation, so as not to affect the venous return of the lower limbs due to the increase of intra-abdominal pressure caused by the difficulty of defecation.