Abstract: Oxytropis ochrocephala, a toxic perennial legume grass, is widely distributed across the grasslands of western China. Developing effective control methods for O. ochrocephala requires exploration of mechanisms contributing to its occurrence. Allelopathy is considered to be an underlying mechanism driving biological invasion in many plant species. In this study, the allelopathic effect of O. ochrocephala on the growth of Medicago sativa and Lolium perenne was analyzed, and the soil bacterial community from the rhizosphere and non-rhizosphere soils of O. ochrocephala were compared to examine if the plants exert allelopathy by altering soil bacterial communities. We planted Medicago sativa and Lolium perenne with soil containing different concentrations of O. ochrocephala tissue powder. After growing for 60 d, plant height, biomass and chlorophyll content were measured. The results showed strong allelopathic effects on the growth of the two grass species with soil containing 5% O. ochrocephala tissue powder, in which plant height, biomass and chlorophyll content were significantly reduced. We compared the bacterial structure of O. ochrocephala rhizosphere and non-rhizosphere soils with 16S rDNA sequencing. The data showed that the structure of the bacterial communities differed greatly and the percentage of some phyla, such as Proteobacteria, Actinobacteria and Acidobacteria, were significantly different. In addition, there were more OTUs (Operational Taxonomic Units) in the non-rhizosphere soil. Since bacteria from different phyla are considered to function discriminately, these changes mean it is highly likely that O. ochrocephala implements allelopathy by altering the structure of the rhizospere bacterial community, and accordingly promotes its growth and competes with other associated plants. These results will assist the development of controlling strategies for O. ochrocephala in the future.