Varicose veins are a venous reflux disease, which refers to the elongated, tortuous and varicose state of veins due to weakness of the vein walls and blood stagnation. The most common type of varicose veins are lower extremity veins. The main causes of varicose veins are weakness in the vein wall, defective valves and increased pressure in the superficial veins. First of all, weakness of the vein wall and venous valve defects are related to genetic developmental factors. Because of the relative weakness of the vein wall, it can expand under the action of venous pressure, and the expansion at the valve sinus causes the original venous valve to fail to close tightly, valve dysfunction occurs, and blood flows backwards. If the valve is poorly developed or absent, it also cannot play an effective role in preventing backflow, which can lead to its development. Secondly, the persistent elevation of intravenous pressure is mainly related to acquired factors such as long-term standing work, heavy physical labor, pregnancy, long-term constipation, and chronic cough. The venous blood itself, due to gravity, exerts a certain pressure on the valve, which normally does not cause damage to it, but when the intravenous pressure continues to rise, the valve is subjected to excessive pressure and gradually relaxes, prolapses, and makes it close poorly. Frequent overload of circulating blood can also cause elevated pressure and venous dilatation, resulting in relative valve closure insufficiency. There are also some predisposing factors such as obesity, advanced age, and female pregnancy and childbirth, which are also indirect factors of varicose veins. There are many causes of varicose veins, which are multifaceted and long-term effects. In daily life, we should avoid sitting and standing for a long time, and wear medical elastic stockings during special periods such as pregnancy to pay attention to the prevention of varicose veins.