The main characteristic of superficial vein thrombosis is pain at the site of thrombosis, with the appearance of a reddened, hypothermic cord with tenderness and surrounding redness in the superficial vein. The following is a description of the etiological mechanism. The disease is divided into two types: infectious and non-infectious. The infectious ones are mostly seen after acute infection, childbirth, pelvic or abdominal surgery, while the non-infectious ones are due to blood stagnation and are mostly seen in the veins of the posterior calf. The decrease in venous reflux pressure in the calf due to various causes, increase in blood viscosity and platelets, and increase in blood coagulation. When the vessel is slightly injured, platelets can be induced to adhere locally to form a thrombus, followed by fibrin deposition that increases the size of the thrombus and leads to lumen occlusion. It may even spread to nearby or distant veins.