Saphenous varicose vein is a common disease in vascular surgery, and about 25% of women and 15% of men in China suffer from this disease. The traditional high saphenous vein ligation with stripping is effective, but it is highly invasive, slow to recover and leaves significant surgical scars. In recent years, with the development of minimally invasive technology and the advancement of treatment concept, various minimally invasive procedures have emerged. Foam sclerotherapy for varicose veins in the lower extremities is gaining more and more attention from medical professionals and patients because of its advantages of being simple, easy to perform, economical and repeatable. Features: 1. Sclerotherapy is the least invasive treatment; 2. 90% of spider veins and reticular veins can be improved by sclerotherapy; 3. Foam sclerotherapy is more effective than liquid sclerotherapy; 4. Repeated sclerotherapy can achieve better results if complete closure of the vein is not achieved at the beginning of treatment; 5. Discharge can be made after 6-12 hours of observation. Sclerotherapy is the targeted removal of varicose veins by sclerotherapy injection into intradermal, subcutaneous and/or intrafascial penetrating veins as well as the sclerosis of varicose vessels under the fascia in patients with venous malformations. All kinds of sclerosing agents can cause significant endothelial damage and may damage the whole vascular foam sclerosing agent is a mixture of one or more gases and liquid sclerosing agents with surface activity, which can drain the blood equivalent to its own volume (gas + liquid sclerosing agent) from the lumen of the vessel after injection into the diseased vessel, and is not easily diluted by blood and washed away by blood flow, so the contact area with the endothelium of the vessel The contact area is increased, and the contact time is prolonged, which improves the efficacy but reduces the amount of sclerosing agent, thus reducing adverse reactions. At the same time, the foam sclerosing agent can rapidly induce vasospasm, further enhancing the sclerosing efficacy. It is simple, easy to perform and economical.