The invention discloses a plant feed additive capable of promoting gastrointestinal digestive functions of weaned piglets and an application thereof. The plant feed additive capable of promoting the gastrointestinal digestive functions of the weaned piglets is characterized by comprising the following raw-material ingredients in percentage by weight: 35-45% of hawthorn fruits, 10-15% of medicated leaven, 4-9% of liquorice roots, 10-15% of poria cocos, 5-8% of dried orange peel, 5-8% of fructus forsythiae, 5-8% of semen raphani, and 4-9% of malt. The ingredients in the natural plant feed additive disclosed by the invention are all common plants, and thus, the plant feed additive is a green and safe feed additive. Dosages of the natural plants are determined according to drug property theories of the natural plants and correlations between the plants, and thus, the drugs are rationally matched. Being applied, the plant feed additive disclosed by the invention is capable of improving the gastrointestinal digestive functions of the weaned piglets, reducing diarrhea rates of the weaned piglets, and increasing production performance of the piglets.