Fecha de publicación: -- Fuente: WIPO "tomato" The present disclosure belongs to the technical field of microorganisms, and in particular relates to a nano-coated growth-promoting bacterial agent and a composite growth-promoting bacterial agent, preparation methods and use thereof. The nano-coated growth-promoting bacterial agent includes a growth-promoting bacterial agent and a nano-coating formed by self-assembly of a plant-derived polyphenol and a soluble multivalent metal ion on the surface of the growth-promoting bacterial agent. The key to the present disclosure is to employ the plant-derived polyphenol and the soluble multivalent metal ion to self-assemble on the surface of the growth-promoting bacterial agent to form a nano-coating. Based on the interaction of the growth-promoting bacterial agent with the phyllosphere, the leaf face adhesion performance of the growth-promoting bacterial agent is significantly enhanced, the loss rate of the growth-promoting bacterial agent under rainfall erosion is effectively reduced, and the survival rate and colonization of the growth-promoting bacterial agent in the phyllosphere are enhanced.