The invention relates to a food or functional food composition, and the composition is prepared from the following raw materials in parts by weight: 250-400 parts of radix ophiopogonis, 250-400 parts of wolfberry fruits, 250-400 parts of alpinia oxyphylla, 250-400 parts of polygonatum sibiricum and 100-250 parts of walnut. The invention also provides a preparation method and application of the composition. The composition overcomes the defects that the radix ophiopogonis, the polygonatum sibiricum and the alpinia oxyphylla in the prior art are poor in mouthfeel and difficult to accept by people, and the composition has better functional effects than commercially available walnut beverages and the like, can effectively improve the memory capacity and improve the hypoxia tolerance, and is capable of nourishing yin, promoting the production of the body fluid, improving vexation and insomnia, and the like. The functional food provided by the invention is good in mouthfeel, unique in flavor, simple in preparation process, easy to carry, suitable for long-term consumption, and good in commercial application prospects.