Hazelnut is one of the "four big nuts", which has the characteristics of rich nutritional value and good flavor and is a good raw material for food processing. There are about 16 species of hazelnuts in the world, mainly distributed in Asia, Europe and North America. As an important producing area of hazelnut in China, there are 8 species and 2 varieties, mainly distributed in Northeast China, North China, Northwest China and Southwest China. European hazelnut has the characteristics of large fruit, beautiful appearance and rich nutrition, and has high commercial value, but it is not suitable for China's climate after years of introduction test. Corylus heterophylla is the most economically valuable resource among wild Corylus heterophylla originated in China, with good cold resistance, but small fruit, thick shell and low kernel rate.