Arbuscular mycorrhizal fungus(AMF)is an important microorganism in ecological and agricultural systems,and it is well known that AMF inoculation can improve nutrient status of host plants.Recent researches show that the inoculation can improve quality of vegetable lants,but its role can be affected by the types of symbiosis,chemistry and physics aracter of soil and agricultural practice.Its mechanism relies on AMF inoculation to rove host plant nutrient status,to change carbon flux of the host plant,to influence host plant enzyme metabolize,to change plant hormone metabolism and the extrinsic nature of AMF.