The Southern Ocean (SO) is the largest ocean in the world. Due to the lack of understanding, traditional viewpoints tend to consider that the SO has little relationship with the climate of the Northern Hemisphere (NH) and thus very weak global climatic impacts because it appears too far away from the NH. With the improvement of observational analyses, numerical simulations and theoretical investigations, and our increasing knowledge about the SO, worldwide climatic impacts of the SO have gradually become prominent. In this paper, we review the role of SO physical processes especially dynamic processes in global climate system by discussing the influences of the Antarctic Bottom Water, the Antarctic Circumpolar Current, sea ice in the SO, and Antarctictropics teleconnections as well as the response of the SO to global warming. We try to completely summarize the understandings of the SO′s climatic impacts. Additionally, based on the research level of the SO, some valuable scientific issues and potential research topics in future studies are also discussed in order to emphasize the role of the SO in global climate and push the study of the SO to move forward.