Microplastics are an emerging pollutant that poses a potential environmental risk to soil ecosystems due to the widespread use and improper handling of plastic materials. Microplastics provide new habitats for microorganisms in the soil and form a unique ecosystem—plastisphere. Due to the special properties of artificial plastics, it is not easy to degrade in the soil environment, which makes the plastisphere pose a serious and lasting ecological threat to the original soil environment. However, recent research on the plastisphere has focused on aquatic ecosystems. Understanding of the effects of soil plastisphere on microorganisms, microplastics, and the combined effects of soil environment and other pollutants is still very limited. This paper reviews the research progress on the ecological risks of the plastisphere as a new habitat for soil microorganisms. This paper mainly discusses the selection effect of soil plastisphere on microorganisms and the migration and transformation of microplastics, the changes of soil structure and soil carbon cycle caused by soil plastisphere, and the combined effect with other environmental pollutants. The purpose of this study is to summarize the mechanism of interaction between microorganisms and microplastics in the soil plastisphere and the subsequent ecological effects, and to provide valuable guidance for future research on the plastisphere of soil ecosystems.