Microplastics are almost ubiquitous in the environment. Their pollution of the environment has aroused grave concerns the world over. However, little has been reported in the literature on microplastics in the terrestrial environment, especially in farmland soil, compared with those in the marine and other aquatic environments. Presumably, microplastic pollution may be more serious in the terrestrial environment than in the aquatic environment. This paper is to make a comprehensive and systematic review of research progresses and future directions of the study on microplastics in the terrestrial environment, to introduce status of the pollution, and accumulation and distribution of microplastics in the soil both in China and in other countries as well, to explore their sources in the terrestrial system, including the use of agricultural film, the application of sludge and organic materials as manure, the irrigation with sewage, and surface runoff and to discuss in detail their interactions with other pollutants (heavy metal and organic pollutant), processes of their accumulation, migration, weathering, and degradation in the soil. Moreover, this paper also elaborates ecological effects of microplastics in soil, impacts of microplastics on soil physico-chemical properties, threat of microplastics to animals, plants, and microorganisms living in the soil and potential risks of microplastics to human health via the respiratory exposure and food-chain. In the end, the paper puts forward views and prospects of future researches on microplastics in the soil environment. This paper is expected to be able to provide information and scientific guidance for comprehensive understanding of the presence and future of microplastics in the soil environment.