Abstract: Disclosed in the present application is a device and method for host-inducing over-expressing of arbuscular mycorrhizal fungal genes, the device including a mycorrhizal chamber and a hyphal chamber arranged above and below, wherein a bottom of the mycorrhizal chamber is defined with hyphal holes, and a support mesh and a nylon mesh are provided on the hyphal holes, allowing the hyphal to pass through but limiting the passage of a plant root system. The nurse plants were cultured in the mycorrhizal chamber and inoculated with an AM fungal microbial inoculum and watered with a low-phosphorus nutrient solution; a high-phosphorus nutrient solution was injected into the hyphal chamber. Subsequently, a target host plant over-expressing the AM fungal gene is introduced such that the target host plant is joined into the symbiotic network with a high speed of nutrients exchange with the AM fungal hyphae.