Abstract: Trunk injection with chemicals is a method of passing inject supply nutrition liquid, plant growth regulators, pesticides and other substances in tree trunk relying on the transpiration pulling force and external force, it can be used to control tree disease and pest insects, strengthen nutrient supply, treat element deficiency, regulate plants growth. The theories,injection apparatus,characters,applications and key techniques with the techniques of trunk injection of chemicals were introduced in detail. With the function of trunk injection and its apply to practice study thoroughgone, the injection apparatus improved, the key to the technique resolved, it has already come to mature and was paid more attention by many managers in the orchards and forestry.