Objective To screen the active components of Bushen Huoxue Decoction ( BSHXD) involved in promoting the proliferation of bone marrow mesenchymal stem cells ( MSCs). Methods BSHXD and its subdivisions were extracted with petroleum ether, ethyl acetate, water-free ethanol and water respectively. MSCs were isolated and cultured by the bone marrow adherent method. At the third passage, MSCs were identified by the specific surface markers with immunofluorescence, and their osteogenic and adipogenic differentiation were tested by alizarin red staining and oil red “O” staining. After treated with the extracts of BSHXD and its subdivisions at gradient concentrations for 24 hours, cell viability was detected by methyl thiazolyl tetrazolium (MTT) assay for the screening of active components and optimal concentration. MTT assay was used to describe the growth curve of MSCs treated with the most effective components, and cell cycle was analyzed by flow cytometry. Results Compared with the blank control group, the extracts of BSHXD and its subdivisions could protect MSCs from death to various degrees. Of all the extracts, the ethyl acetate extract of Bushen Division ( BSD) , ethyl acetate extract of BSHXD, ethyl acetate extract of Huoxue Division ( HXD) had the strongest effect, and the effect was dose-dependent, 100 μg/mL being the optimal active concentration while having no any cytotoxic reaction. The results of MTT assay revealed that BSD extracts promoted the proliferation of MSCs significantly and was the most effective component, and then came BSHXD. The results of flow cytometry indicated that BSD extract had the most strongest effect on increasing the amount of MSCs at proliferative phase, and then came BSHXD. Conclusion BSD ethyl acetate extract is the active component of BSHXD for promoting the proliferation of MSCs, showing an effect on increasing the proportion of MSCs at proliferative phase.