Authentic Chinese yam is originated in Huaiqing area of Henan Province. In the Qin and Han dynasties, "Shennong Ben Cao Jing" recorded: yam to Henan Huaiqing good. Jiaozuo is known as Huaiqingfu, north of Taihang, south of the Yellow River, natural conditions are unique, yam, dihuang, chrysanthemum, hyssop, "four big yam" is famous in China and abroad.

The main constituents of yam are starch 16% (amylase), protein (which sugar protein including 16 amino acids), sugar (mannose, glucose, galactose), saponin mucus, vitamins, iron and manganese and other trace elements and other components, there are dry and straight, white color, powdery enough and so on.