Abstract: The research took Tangshan introduction of Bupleurum chinense as the sample to study the dynamic change law of saikosaponins and saikosaponin a, d of different parts and discuss the optimal harvest time of Bupleurum chinense. The content of saikosaponins and saikosaponin a, d was determined by UV- visible spectropholometry and HPLC method. The root, stem and leaf contained saikosaponin, the content of saikosaponin in the whole growth period was fluctuated, but the overall trend was on declining. There were obvious difference in different parts and different harvest time, the content in root was more than that in stem and leaf. The content in stem was the lowest. The content of saikosaponin d in root were higher than that of saikosaponin a; the content of saikosaponins and saikosaponin a, d was the highest in October of the first year, and was the lowest in September of the second year, the content of saikosaponin a and d was higher in August. The determination methods of saikosaponins by UV-visible spectrophotometry and saikosaponin a and d by HPLC was proved to be feasible and the result was good. The optimal harvest period of introduction Bupleurum chinense was determined, which could provide scientific basis for harvesting and production.