In recent years, plastic pollution has become an environmental issue of global concern. The pollution of microplastic (MPs) in the terrestrial ecosystems, especially in agroecosystems, has attracted increasing attention. Due to their low degradability, MPs accumulate in soil and render damages to soil ecosystems, thus posing health risks for human and animals through food chains. The present paper first introduces sources of MPs in soils, including plastic film mulching, application of sewage sludge and organic manure, irrigation with wastewater, atmospheric deposition, and surface runoff. Then it goes on to elaborate distribution and abundance of MPs in soil environments, particularly in agricultural soils, and discuss migration of MPs in terrestrial environments, with focuses on direct and indirect ecological effects of MPs on soil-plant systems. Current available evidence shows that MPs can directly change soil physio-chemical properties, and affect microorganisms and enzyme activities, soil fauna, seed germination, and root uptake of water and nutrients, and moreover they can be accumulated and translocated upwards, thus causing toxic effects on the plants. MPs can also indirectly affect plants via changing soil properties and interacting with other soil pollutants such as heavy metals. In the end, the paper discusses directions of the research on MPs in soil-plant systems in future. Moreover, this paper is expected to be able to provide a theoretical basis and scientific guidance for better understanding the ecological effects of soil MPs and controlling their potential risks.