Sclerotherapy, first proposed by Cassaigness in 1853, involves the injection of a chemical sclerosing agent into the varicose vein to cause a secondary inflammatory response in the vein wall, followed by continuous postoperative compression to cause the vein to atrophy and subsequent fibrosis of the granulation tissue within the lumen of the atrophied vein, eventually forming fibrous cords to treat the varicose vein. In the past, sclerosing agents were mostly selectively applied to patients with mild varicose veins such as reticular varicose veins, capillary dilation or as an adjunct to surgery, and often could not be applied to the main trunk of saphenous veins, which had problems such as pain, local irritation, poor venous closure and deep vein thrombosis, which greatly limited the application of sclerotherapy. The emergence of new sclerosing agents has brought about a dramatic change in the therapeutic effect of sclerotherapy. Foam sclerotherapy is a new foam sclerosing substance formed by mixing liquid sclerosing agent with gas, which can avoid a series of complications such as deep vein thrombosis, and has become one of the most important developments in the field of phlebology in the past 10 years with its high efficiency, rapidity, safety, affordability, repeatability, and scarlessness, etc. The 2nd European Coordination Meeting on Foam Sclerotherapy held in April 2006 considered that foam Sclerotherapy has been revived as a minimally invasive treatment for varicose veins, and the use of foam sclerotherapy in various types of varicose vein disease is recognized worldwide for its safety and effectiveness. The safety and efficacy of this technique is greatly enhanced by the fact that foam sclerotherapy is performed by an interventionalist under imaging guidance. Foam sclerotherapy is indicated for all types of varicose veins and venous malformations, especially in young women with cosmetically demanding varicose veins.