Abstract: The flower buds and functional leaves of Cymbidium sinense ‘Qi Jian Bai Mo’ during flower bud differentiation were used as experimental materials.The dynamic changes of starch, soluble sugar, soluble protein content, CAT and POD activities and endogenous hormones in functional leaves during flower bud differentiation were analyzed, in order to provide reference for the regulation mechanism of flower formation of Cymbidium sinense.The results showed that the flower bud differentiation of ‘Qi Jian Bai Mo’ could be divided into six phases, undifferentiation phase, inflorescence primordium differentiation phase, flower primordium differentiation phase, sepal primordium differentiation phase, petal primordium differentiation phase and column and pollinia primordium differentiation phase.During flower bud differentiation, the contents of starch, soluble sugar and soluble protein in functional leaves showed an up-down-up trend.CAT and POD activities were at a high level.Gibberellin（GA₃） content decreased, while auxin（IAA） content continued to increase and remained stable.Abscisic acid（ABA） content was an overall upward trend.In conclusion, the accumulation of carbohydrate and soluble protein was beneficial to induce flower bud formation, and flower bud morphogenesis required to consume of a large amount of sugar and soluble protein.CAT and POD with high activity could ensure flower bud differentiation smoothly.The low level of GA₃ and high level of IAA and ABA could induce flower bud development, and high level of GA₃,IAA and ABA play an important role in the differentiation of perianth primordia.