Abstract: This paper studies the changing rule of endogenesis spermidine (Spd) content in autumn-cutting chrysanthemum Jinba' in apical buds and leaves during floral bud differentiation, meanwhile analyses the effects of Spd and dicyclohexylamine (DCHA) on the process of floral bud differentiation of Jinba' as well as the changing rule of carbohydrates and soluble protein content. The results showed that, high levels of Spd in apical buds was accumulated during the initiative stage of floral bud differentiation and the stage of floret primordia differentiation, while the levels of Spd in leaf were lower. After short day treatment, the content of carbohydrates increased and the content of soluble protein decreased. The content of carbohydrates and soluble protein were increased by exogenous Spd, promoting the soluble protein reached its highest levels in advance, then promoted floral bud differentiation. The DCHA treatment had the opposite result compared with Spd. These results provide a theoretical basis for the development of chrysanthemum.