Varicose veins are mostly caused by the accumulation of blood in the lower limbs due to maintaining the same posture for a long time with little change, and the high venous pressure is caused by the destruction of the venous valves over time. The main causes of the disease are: 1. Weakness of the vein wall and valve defects: the vein wall is relatively weak and can expand under the action of venous pressure, and the expansion at the valve sinus leads to the inability of the original venous valve to close tightly and the occurrence of relative valve insufficiency and backflow of blood. Valve dysplasia or absence, also can not play an effective role in preventing backflow, leading to the onset. 2, venous pressure persistently elevated: venous blood itself due to the role of gravity, a certain pressure on the valve, under normal circumstances will not cause damage, but when the venous pressure continues to rise, the valve will withstand excessive pressure, gradually relaxation, prolapse, so that the closure is incomplete. This is mostly seen in long-term standing work, heavy physical labor, female pregnancy, childbirth, chronic cough, long-term constipation, etc. 3, followed by age, gender: because the limb venous pressure only reaches the highest pressure when the body length reaches the highest, the body is not high before puberty, so the caliber of veins is small, all can prevent the expansion of veins, so although there are suffering from serious varicose veins before 30 years old, but most of them are gradually losing their tension with age, the vein wall and valves, and the symptoms increase forcing patients to seek medical attention. The causes of varicose veins are related to a variety of factors, and those that can be prevented need to be addressed.