Walnut has the functions of improving learning and memory, protecting nerve cells, regulating cholinergic dysfunction, antioxidant, anti-inflammatory and so on. It is a traditional brain-invigorating food. The main functional ingredients of walnut are known as ellagic acid, oleic acid, linoleic acid, linolenic acid, melatonin, vitamin E, syringic acid, caffeic acid, ferulic acid, sinapic acid, coumaric acid, etc. And the main functional target of walnut is prostaglandin synthase. There are more than 300 invention patents for walnuts to improve memory, of which more than 40 are authorized, and 16 health food approvals. However, the identification of walnut functional ingredients is still limited to linoleic acid, linolenic acid and protein, and the recognition of other memory functional ingredients and contents remains to be studied.