The invention discloses usage of active components of Chinese yams as a gastrointestinal mucosal injury improving agent; and the invention further discloses nano starch microspheres containing the active components of the Chinese yams, as well as application of the nano starch microspheres containing the active components of the Chinese yams in preparation of functional foods with improvement effects on gastrointestinal mucosal injury. The active components of the Chinese yams prepared by compounding four Chinese yam active ingredients, namely PC1-PC4, extracted from Chinese yam peel powder inspecific weight ratio can be used as the gastrointestinal mucosal injury improving agent. Being prepared into nano starch microspheres of the active components of the Chinese yams and added into functional foods, the nano starch microspheres of the active components of the Chinese yams are capable of achieving significant gastrointestinal mucosal injury improvement effects; and moreover, being loaded on the nano starch microspheres by adopting a self-assembly technology of starch nanospheres, the functional foods finally prepared with the active components are endowed with sustained-release gastrointestinal mucosal injury improvement effects. In addition, the functional foods prepared with the active components are long-lasting in functions, so that application of the active components ofthe Chinese yams in the market is greatly expanded.