The invention discloses trunk injection insecticidal micro-emulsion granules for preventing and controlling tree pests, a preparation method and an application thereof. The insecticidal micro-emulsiongranules contain the following components, by weight percent, active ingredients 9.5-12.5%, emulsifier 9.5-14.5%, co-solvent 6-8% and filler 65-72%, wherein the active ingredients are emamectin benzoate and/or neonicotinoid insecticides, and the weight percent of the above components is based on the total weight of the insecticidal micro-emulsion granules. According to the insecticidal micro-emulsion granules, a novel solid preparation is prepared by adjusting the contents of the active ingredients, the emulsifier, the co-solvent and the filler, wherein the novel solid preparation has a certain shape and good physicochemical stability, and can be effectively absorbed by plant tissues and passed to a target location by virtue of transpiration and diffusion in the tree body.