Purple blood vessels on the inner thighs are actually a mild manifestation of varicose veins. The purple blood vessels are clinically referred to as capillary dilation and are a sign of early or precursory varicose veins. The main cause is the same as the cause of varicose veins, which is due to congenital thinning of the vein wall, formation of intravenous hypertension, venous valve insufficiency or valve malfunction, resulting in lower extremity venous reflux obstruction, which will gradually form relatively mild varicose veins like the purple veins on the inner thighs. With the development of the disease, the veins of the lower extremities will gradually become obvious and even tortuous and dilated, which is called pathological varicose veins. In addition, apart from congenital factors, acquired risk factors, such as the nature of standing and standing work, lack of exercise, obesity, women during pregnancy, long-term oral hormonal drugs, these risk factors can also slowly trigger the occurrence of varicose veins. Therefore, if there are purple veins in the inner thighs, they usually do not cause serious adverse consequences, but they should be treated systematically and regularly in the vascular surgery department of a specialized hospital.