To know how to prevent deep vein thrombosis, we must first understand what is deep vein thrombosis? Deep vein thrombosis is the abnormal clotting of blood in the deep veins and is a disorder of venous return in the lower extremities. Thrombosis occurs mostly under braking conditions (especially in major orthopedic surgery). The three main factors are slow blood flow, damage to the venous wall and hypercoagulable state. After thrombosis, except for a few that can ablate on their own or are limited to the site of occurrence, most of them will spread to the deep vein trunk of the whole limb. If they are not diagnosed and treated in time, most of them will evolve into thrombosis sequelae, which will affect the quality of life of patients for a long time; some patients may have pulmonary embolism as a complication, causing extremely serious consequences.