1. Appearance: the shell of Carya cathayensis is hard and brown, and its shape is similar to that of walnut, while the shell of small walnut is thin and grayish brown, and its shape is similar to that of hazelnut.

2. Nutritional components: Carya cathayensis is rich in unsaturated fatty acids, vitamin E, zinc, magnesium and other nutrients, while walnut is rich in protein, vitamin B 1, B2, B6, calcium, iron and other nutrients.