Abstract: Chemical compositions of being produced tea by Dandelion leaves picked at March and May, from Siyang district were determined and analyzed.Dandelion leaves picked at April and June was also studied at the same conditions.Dumas combustion, Folins' method, Aluminium nitrate method, Phenols- sulfate method, DNS, HPLC, GC-MS, ICP- AES and National standard method ( GB /T 6433- 2006) etc., were employed to detect and analyze the compositions, such as crude protein, total phenols, total flavones, water- soluble polysaccharide, reducing sugar, organic acid, crude fiber, crude fat and volatile composition, ash content and mineral elements in the raw materials. The results showed that the dandelion tea and leaves were rich in protein, total phenols, total flavones and polysaccharides.However, crude fiber and ash content in the tea and leaves were little.Additionally, a wide variety of organic acid, i.e., chlorogenic acid, caffeic acid, coumaric acid and gallic acid were contained with high content.The volatile compositions mainly consisted of fatty acid, hydrocarbon with long chain fatty and olefins, also kind of caffeine and phenols.Besides, the minerals from the tea and leaves were sufficient for Ca, K and P, not possessing As, Hg and Pb of heavy metal elements.Dandelion leaf is excellent natural resource with homology of medicine, which has more extensive applications in the area of food, pharmaceutical and cosmetics in future.