Typically, it takes about 7-14 days for a thrombosis of the intermuscular veins of the calf to pass through the danger period. During the period of risk of CVT, the blood clot in the body is extremely unstable and can be dislodged from the blood vessel by any activity or stimulation of the leg. The dislodged thrombus usually travels with the venous circulation to the pulmonary artery, which can lead to a fatal pulmonary embolism. Strict bed rest and lower extremity braking are recommended during the acute phase to minimize the risk of pulmonary embolism, and prompt and adequate anticoagulation is recommended. Subcutaneous injections of low molecular heparin and rivaroxaban can be used under the supervision of a doctor to prevent new thrombosis, and the use of drugs can also promote the ablation of existing thrombus. In addition, after 7-14 days of bed rest, the thrombus has passed the dangerous period and the condition is relatively stable, it is recommended to start to get out of bed to carry out moderate activities, and avoid strenuous activities.