Abstract: In seeds of Bupleurum chinese, some problems exist such as low germination rate and high inembryonate rate. To investigate the reasons for these problems, the phases of inflorescence differentiation and the variation of differentiation processes between inflorescences at different positions were studied. Inflorescence differentiation can be divided into 6 phases: primary, rundlet primordium, floret primordium, pistil and stamen primordium, initial reproduction structure and pollen maturation. Meanwhile, the lower branch inflorescences fell behind the upper ones in differentiation at least for one phase during differentiation. The failure of synchrony in differentiation processes between inflorescences at different positions leads to nonconformity in stage and degree of seed maturity, which is the important element affecting seed quality in B. chinese. So regulation of the differentiating inflorescences in different positions by artificial methods may be practical for improving seed quality.