Through the study of symbiosis of AMF (Arbuscular mycorrhizal fungi)-Amorpha fruticosa, the infection sequence, the infection rates and the chemotaxis between AMF and rhizobia had been determined. The diversity of infection between AMF and rhizobia in time-space under the inoculation conditions of mon-innoculation (AM+) and dipl-innoculation (AM++Rh+) was investigated and the relationship between AMF and rhizobia in the chemotaxis test was studied. The results suggested that there were some signals beween AMF and rhizobia and there exsited auxoaction in coordination during the formation of symbiosis. The chemotaxis between the root-exudates and rhizobia under the inoculation conditions of AM-+Rh-, AM+ and AM++Rh+ in 25℃, 28℃, 31℃ showed that the surrounding conditions (temperature) in rhizosphere have some effects on the regulation of incipient identification signals in the tri-symbiosis of AMF-host- rhizobia.