Abstract: The dynamic changes of endogenous hormone content during flower bud differentiation were studied in Lycoris radiata while the bulb was anatomized. The relationship between the endogenous hormones and nucleic acid’ s content was analysed. The results showed that the peak of endogenous hormones content was IAA,ABA in former differentiation stage, GA in forming for stamen and ZR in forming for pistil in flower bud morphogensis. The nucleic acid content peak followed. It presented endogenous hormones regulated nucleic acid metabolism progress. IAA and ABA were the most important facts in flower bud differentiation progress. The high ratio of ABA to GA accelerated both forming differentiation and development of flower bud formation. High ratio of IAA to ZR and ABA to ZR accelerated flower bud formation,but it went against stamen and pistil formation. All these Showed that. the content of the four endogenous hormones varied remarkably and achieved a balance at the end. The flower bud differentiation was finished at the end.