Abstract: In order to establish efficient cutting technique system of Syringa microphylla, contents of 4 kinds of endogenous hormones (IAA、GA、ABA and ZR) in the process of adventitious root organogenesis were determined by hplc. The result showed that the contain of endogenous substance changed dynamically, in which the content of IAA and ZT increased first, then reduced, and finally rose slowly;but the content of ABA and GA3continued to decrease with fluctuation in the entire process. In the entire process of the adventitious root organogenesis, the tendency on the ratio of IAA/ABA went up continuously. The high activities of IAA, ZR and the ratios of IAA/ABA played a dominant role to promote the adventitious roots.