As a bottom-up constructed microbial community, the synthetic microbial system has the characteristics of low complexity, controllability and operability compared with natural microbial communities. It is an emerging biotechnology and draws on synthetic biology, systems biology, biological evolution and other knowledge. Furthermore, by rational designing, planning and regulating, it becomes an experimental platform for studying microbial ecology theory, and a microbial system for validating known theories. In this paper, we first briefly introduce the concept of synthetic microbial system and its origin, expound its basic construction principles. We then introduce its ecological theoretical basis, and summarize its applications in recent years. Finally, we present our outlook on the development of synthetic microbial system, including the need to design and construct more complex synthetic microbial communities, and to optimize ecological models.