Using the flower buds of Huizao and Junzao as materials, we determined the changes of soluble sugar, reducing sugar, starch, soluble protein contents, SOD, POD, PPO, CAT activities and endogenous GA₃, IAA, ABA, ZT contents in flower buds at different differentiation stages, and discussed their relations with flower bud differentiation, so as to provide theoretical reference for the regulation of flower bud differentiation of Zizyphus jujuba. The results showed that: (1) the changes of soluble sugar, reducing sugar and starch contents of Huizao and Junzao during flower bud differentiation were basically similar. The contents of soluble sugar, reducing sugar and starch first decreased and then increased from flower primordium differentiation stage to pistil differentiation stage, and reached the peak at pistil differentiation stage; On the contrary, the contents of protein and carbohydrate first increased and then decreased from flower primordium differentiation stage to pistil differentiation stage. (2) With the beginning of flower bud differentiation, the activities of POD, PPO and CAT decreased gradually, and the lowest point appeared in pistil differentiation stage; the activity of SOD increased significantly from primordium differentiation stage to early differentiation stage, and then the activity of SOD decreased in Huizao, while increased in Junzao significantly. (3) The changes of IAA, GA₃, and ZT contents during flower bud differentiation are basically similar. IAA, GA₃, and ZT show a downward trend before the sepal differentiation stage, and then the contents of GA₃, ZT and content of IAA in Huizao increased gradually, while the content of IAA in Junzao first increased significantly, then decreased and then increased from sepal differentiation stage to petals differentiation stage; the content of ABA increased significantly from primordium differentiation to sepal differentiation, but decreased significantly in Junzao. With the advance of differentiation, ABA content of Huizao decreased gradually after sepal differentiation, while increased gradually in Junzao and reached the peak at pistil differentiation. (4) With the beginning of flower bud differentiation, the ratios of ABA/IAA, ZT/IAA and GA₃/IAA increased rapidly, but the ratios of GA₃/ABA and ZT/ABA decreased; The ratios of ZT/IAA and GA₃/IAA were significantly increased and then decreased from primordial differentiation stage to sepal differentiation stage. After differentiation, the ratios of ZT/IAA and GA₃/IAA were lower than those at primordial differentiation stage. The results suggested that after the flower buds of jujube start to differentiate, they consume a lot of nutrients, the soluble sugar, starch and reducing sugar contents of the flower buds are reduced, and the starch content is always higher than the soluble sugar and reducing sugar during the whole differentiation process. The decrease of POD, CAT, PPO activities during the flower bud differentiation process of the two varieties, and the increase of SOD activity during the flower bud differentiation process of Junzao, are conducive to the transition from vegetative growth to reproductive growth; In the process of jujube flower bud differentiation, low levels of GA₃ and IAA, medium level of ABA, higher level of ZT and high ratios of ZT/IAA, ABA/IAA and GA₃/IAA are beneficial to the differentiation and formation of jujube flower buds.