The present invention relates to a composition containing an onion skin hot-water extract as an active ingredient for preventing, alleviating, or treating diabetes and blood vessel diseases, wherein the onion skin hot-water extract is verified to have effects on weight, the control of blood sugar, the improvement of blood lipid, and antioxidative activity, and thus can be used as a functional raw material for a functional health food for preventing, alleviating, or treating diabetes and blood vessel diseases. Particularly, the present invention relates to a composition containing an onion skin hot-water extract as an active ingredient for preventing, alleviating, or treating diabetes and blood vessel diseases, wherein the onion skin hot-water extract is obtained by preparing an onion skin solution having a concentration of 10-20 mg/ml using purified water, followed by hot-water extraction at 80-100°；C and pH of 6-7 for 30-60 minutes. The present invention provides a composition containing an onion skin hot-water extract as an active ingredient for preventing, alleviating, or treating diabetes and blood vessel diseases, thereby improving the suppression of weight, the control of blood sugar, the improvement of blood lipid, antioxidative activity, and endurance, thus preventing, alleviating, or treating diabetes and blood vessel diseases. Further, the present invention provides a method for an onion skin hot-water extract wherein bioactive substances, including quercetin, contained in the onion skins in an eco-friendly, low-cost, and efficient manner. Further, the present invention provides a functional health food composition for preventing, alleviating, or treating diabetes and blood vessel diseases by containing the onion skin hot-water extract as an active ingredient and adding a food auxiliary additive thereto.본 발명은 양파껍질 열수추출물이 체중, 혈당조절, 혈중 지질개선 및 항산화력에 미치는 효과를 확인함으로써, 당뇨병 및 혈관질환 예방, 개선 또는 치료를 위한 건강기능식품의 기능성 원료로 활용할 수 있는 양파껍질 열수추출물을 유효성분으로 함유하는 당뇨병 및 혈관질환 예방,
