The invention relates to a 
euonymus alatus extract and a preparation process, a 
quality control method, the blood-
sugar-reducing activity of the 
euonymus alatus extract and application of the 
euonymus alatus extract to the preparation of products for reducing 
blood sugar. The euonymus alatus extract can be prepared by any one of a 
solvent extracting method, a macroporous adsorbent resin method, a 
supercritical fluid extraction method, 
column chromatography, liquid-liquid counter-current partition 
chromatography and the like or a combination of the methods. The prepared euonymus alatus extract comprises the following active ingredients: flavonoids, 
phenols, alkaloids, triterpenoids, sterides, organic acids and polysaccharides, wherein the flavonoids and the 
phenols are main ingredients, and the content of general 
flavones is between 5 and 100 weight percent. Blood-
sugar-reducing experiments of mice which suffer from diabetes caused by mesoxyalyurea prove that the raising of the 
blood sugar after the 
intragastric administration of glucose is inhibited effectively, and the euonymus alatus extract has a certain 
treatment effect on experimental diabetes caused by 
pancreas islet beta cell injury caused by the mesoxyalyurea, and can be applied to the preparation of the products for reducing the 
blood sugar.