Abstract: Research achievements were reviewed on arbuscular mycorrhizal fungi (AMF) symbiotic mechanism, and research progress was described on AMF in increasing tolerance to salt, heavy metals, drought and high temperature stress on host plants by enhancing photosynthesis, uptake nutrient elements and water use efficiency. Suggestions were put forwarded on further study on large scale purification and culture technique, selection and identification of different AMF, their operation mechanism and relations as well as on mycobiont of soil-AMF-plant and its mechanism.