Klippel Trenaunay Syndrome (KTS) falls into overgrowth spectrum. Symptoms of it include capillary malformation, phlebeurysma, limb deformity with or without lymphangion malformation. Its causes are mostly related to the genic mutation of somatic cell PIK3CA. KTS has various clinical manifestation, including Port-wine stains and venous thromboembolism—the former can affect appearance and the latter can endanger life. As KTS yet cannot be cured from root causes, the crucial method is to improve the quality of life for patients and reduce the incidence rate of complications. Early diagnosis, imaging assessment and multidisciplinary management can effectively improve the quality of life for patients.